U.S. patent application number 15/973977 was filed with the patent office on 2018-09-13 for semiconductor light emitting device.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Nam Goo CHA, Yong II KIM, Wan Tae LIM, Hye Seok NOH, Eun Joo SHIN, Sung Hyun SIM, Hanul YOO.
Application Number | 20180261738 15/973977 |
Document ID | / |
Family ID | 57281813 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180261738 |
Kind Code |
A1 |
CHA; Nam Goo ; et
al. |
September 13, 2018 |
SEMICONDUCTOR LIGHT EMITTING DEVICE
Abstract
A semiconductor light emitting device includes: a light emitting
structure including a first conductivity-type semiconductor layer
and a second conductivity-type semiconductor layer respectively
providing a first surface and a second surface, opposite to each
other, of the light emitting structure, and an active layer
interposed between the first conductivity-type semiconductor layer
and the second conductivity-type semiconductor layer, a region of
the first conductivity-type semiconductor layer being open toward
the second surface, and the first surface having a concavo-convex
portion disposed thereon; a first electrode and a second electrode
disposed on the region of the first conductivity-type semiconductor
layer and a region of the second conductivity-type semiconductor
layer, respectively; a transparent support substrate disposed on
the first surface of the light emitting structure; and a
transparent adhesive layer disposed between the first surface of
the light emitting structure and the transparent support
substrate.
Inventors: |
CHA; Nam Goo; (Hwaseong-si,
KR) ; LIM; Wan Tae; (Suwon-si, KR) ; KIM; Yong
II; (Seoul, KR) ; NOH; Hye Seok; (Suwon-si,
KR) ; SHIN; Eun Joo; (Seoul, KR) ; SIM; Sung
Hyun; (Uiwang-si, KR) ; YOO; Hanul;
(Goyang-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRONICS CO., LTD. |
Gyeonggi-do |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Gyeonggi-do
KR
|
Family ID: |
57281813 |
Appl. No.: |
15/973977 |
Filed: |
May 8, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15163204 |
May 24, 2016 |
|
|
|
15973977 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 2224/11 20130101;
F21S 8/026 20130101; H01L 33/0093 20200501; F21V 23/005 20130101;
H01L 33/58 20130101; F21Y 2115/10 20160801; H01L 33/505 20130101;
H01L 33/44 20130101; F21K 9/237 20160801; F21K 9/275 20160801; F21Y
2103/10 20160801 |
International
Class: |
H01L 33/58 20100101
H01L033/58; H01L 33/50 20100101 H01L033/50 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2015 |
KR |
10-2015-0073930 |
Oct 1, 2015 |
KR |
10-2015-0138683 |
Feb 5, 2016 |
KR |
10-2016-0015233 |
Claims
1. A semiconductor light emitting device comprising: a light
emitting structure comprising a first conductivity type
semiconductor layer, an active layer, and a second conductivity
type semiconductor layer, a first through hole being formed inside
the light emitting structure; an etch stop layer disposed on a top
surface of the second conductivity type semiconductor layer of the
light emitting structure, the etch stop layer comprising a second
through hole communicating with the first through hole; a current
spreading layer disposed on top surfaces of the second conductivity
type semiconductor layer of the light emitting structure and the
etch stop layer; a first electrode structure on a bottom surface of
the first conductivity type semiconductor layer and electrically
connected to the first conductivity type semiconductor layer; a
second electrode structure on the bottom surface of the first
conductivity type semiconductor layer and electrically connected to
the current spreading layer through the first through hole and the
second through hole; a transparent adhesive layer on the current
spreading layer; and a transparent support substrate adhered onto
the transparent adhesive layer.
2. The semiconductor light emitting device of claim 1, wherein the
first conductivity type semiconductor layer comprises an n-type
semiconductor layer, and the second conductivity type semiconductor
layer comprises a p-type semiconductor layer.
3. The semiconductor light emitting device of claim 1, further
comprising a graded index layer having a predetermined refractive
index and disposed between the current spreading layer and the
transparent adhesive layer.
4. The semiconductor light emitting device of claim 3, wherein the
graded index layer comprises a multilayer structure of a titanium
oxide (TiO.sub.2) layer and a silicon oxide (SiO.sub.2) layer.
5. The semiconductor light emitting device of claim 3, wherein the
graded index layer comprises an obliquely deposited indium tin
oxide (ITO) layer on a top surface of the current spreading
layer.
6. The semiconductor light emitting device of claim 1, wherein the
transparent adhesive layer has a refractive index between a
refractive index of the first conductivity-type semiconductor layer
and a refractive index of the transparent support substrate.
7. The semiconductor light emitting device of claim 1, wherein the
transparent adhesive layer comprises a wavelength conversion
material converting at least a portion of light having a first
wavelength and generated by the active layer into light having a
second wavelength.
8. The semiconductor light emitting device of claim 1, further
comprising a reflective layer disposed on internal walls of the
first through hole and the second through hole and a bottom surface
of the first conductivity type semiconductor layer.
9. The semiconductor light emitting device of claim 1, wherein the
first electrode structure comprises a first contact layer on the
bottom surface of the first conductivity type semiconductor layer,
and the second electrode structure comprises a second contact layer
in the second through hole.
10. The semiconductor light emitting device of claim 1, wherein the
transparent support substrate is provided with a concave/convex
structure, the concave/convex structure being formed on a top
surface of the transparent support substrate.
11. The semiconductor light emitting device of claim 1, wherein the
transparent support substrate has a semispherical shape.
12. The semiconductor light emitting device of claim 1, further
comprising a wavelength conversion layer disposed between the
transparent adhesive layer and the transparent support substrate
and converting at least a portion of light having a first
wavelength and generated by the active layer into light having a
second wavelength.
13. The semiconductor light emitting device of claim 1, further
comprising a wavelength conversion layer disposed on a surface of
the transparent support substrate and containing a wavelength
conversion material converting at least a portion of light having a
first wavelength and generated by the active layer into light
having a second wavelength.
14. A semiconductor light emitting device comprising: a light
emitting structure comprising a first conductivity type
semiconductor layer, an active layer, and a second conductivity
type semiconductor layer, a first through hole being formed inside
the light emitting structure; an etch stop layer disposed on a top
surface of the second conductivity type semiconductor layer of the
light emitting structure, the etch stop layer comprising a second
through hole communicating with the first through hole; a current
spreading layer disposed on top surfaces of the second conductivity
type semiconductor layer of the light emitting structure and the
etch stop layer to cover the second through hole; a first electrode
structure on a bottom surface of the first conductivity type
semiconductor layer and electrically connected to the first
conductivity type semiconductor layer; a second electrode structure
on the bottom surface of the first conductivity type semiconductor
layer and electrically connected to the current spreading layer
through the first through hole and the second through hole; a
transparent adhesive layer on the current spreading layer; and a
transparent support substrate adhered onto the transparent adhesive
layer, wherein at least one of the transparent support substrate
and the transparent adhesive layer comprises a wavelength
conversion material converting at least a portion of light having a
first wavelength and generated by the active layer into light
having a second wavelength.
15. The semiconductor light emitting device of claim 14, wherein
the transparent adhesive layer has a refractive index between a
refractive index of the first conductivity-type semiconductor layer
and a refractive index of the transparent support substrate.
16. The semiconductor light emitting device of claim 15, wherein
the transparent adhesive layer has a refractive index higher than a
refractive index of the current spreading layer.
17. The semiconductor light emitting device of claim 1, wherein the
transparent adhesive layer comprises a first wavelength conversion
material converting at least a portion of light having a first
wavelength and generated by the active layer into light having a
second wavelength, and wherein the transparent support comprises a
second wavelength conversion material converting at least a portion
of light having a first wavelength and generated by the active
layer into light having a third wavelength
18. The semiconductor light emitting device of claim 14, further
comprising an optical filter layer disposed on a surface of the
transparent support substrate, and blocking light having the first
wavelength and allowing light having the second wavelength to be
transmitted therethrough.
19. The semiconductor light emitting device of claim 18, further
comprising a color filter layer disposed on the optical filter
layer and allowing light partially within a wavelength band of the
second wavelength to be selectively transmitted therethrough.
20. The semiconductor light emitting device of claim 19, further
comprising a light diffusion layer disposed on the color filter
layer and diffusing light emitted from the color filter layer.
21. The semiconductor light emitting device of claim 14, wherein
the transparent adhesive layer comprises at least one material
selected from the group consisting of polyacrylate, polyimide,
polyamide, and benzocyclobutene (BCB).
22. The semiconductor light emitting device of claim 14, wherein
the transparent support substrate comprises a glass substrate.
23. A semiconductor light emitting device comprising: a light
emitting structure comprising a first conductivity type
semiconductor layer, an active layer, and a second conductivity
type semiconductor layer, a first through hole penetrating through
the light emitting structure to connect a top surface of the second
conductivity type semiconductor layer and a bottom surface of the
first conductivity type; an etch stop layer disposed on the top
surface of the second conductivity type semiconductor layer, the
etch stop layer comprising a second through hole communicating with
the first through hole; a current spreading layer disposed on top
surfaces of the second conductivity type semiconductor layer and
the etch stop layer; a first electrode structure on the bottom
surface of the first conductivity type semiconductor layer and
electrically connected to the first conductivity type semiconductor
layer; a second electrode structure on the bottom surface of the
first conductivity type semiconductor layer and electrically
connected to the current spreading layer through the first through
hole and the second through hole; a transparent adhesive layer on
the current spreading layer; a graded index layer having a
predetermined refractive index and disposed between the current
spreading layer and the transparent adhesive layer; and a
transparent support substrate adhered onto the transparent adhesive
layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. application Ser. No.
15/163,204 filed May 24, 2016, which claims priority from Korean
Patent Application Number 10-2015-0073930 filed on May 27, 2015,
Korean Patent Application Number 10-2015-0138683 filed on Oct. 1,
2015 and Korean Patent Application Number 10-2016-0015233 filed on
Feb. 5, 2016 in the Korean Intellectual Property Office, the
disclosures of which are incorporated herein by reference in their
entirety.
BACKGROUND
1. Field
[0002] Apparatuses and methods consistent with exemplary
embodiments of the inventive concept relate to a semiconductor
light emitting device.
2. Description of the Related Art
[0003] In general, semiconductor light emitting diodes (LEDs) are
commonly used as light source due to various inherent advantages
thereof, such as low power consumption, high levels of luminance,
and the like. In particular, recently, semiconductor light emitting
devices have been used as backlight in display devices such as
large liquid crystal displays (LCDs), as well as in general
lighting devices.
[0004] A substrate (hereinafter, referred to as a "growth
substrate") used for epitaxial growth of semiconductor light
emitting devices may be removed due to an electrical connection or
an optical loss problem. In this case, other means may be required
to support an epitaxial thin film.
SUMMARY
[0005] Example embodiments of the inventive concept provide
semiconductor light emitting devices having improved light
extraction efficiency, while retaining a flip chip structure.
[0006] According to an aspect of an example embodiment, there is
provided a semiconductor light emitting device which may include: a
light emitting structure including a first conductivity-type
semiconductor layer and a second conductivity-type semiconductor
layer respectively providing a first surface and a second surface,
opposite to each other, of the light emitting structure, and an
active layer interposed between the first conductivity-type
semiconductor layer and the second conductivity-type semiconductor
layer, a region of the first conductivity-type semiconductor layer
being open toward the second surface, and the first surface having
a concavo-convex portion disposed thereon; a first electrode and a
second electrode disposed on the region of the first
conductivity-type semiconductor layer and a region of the second
conductivity-type semiconductor layer, respectively; a transparent
support substrate disposed on the first surface of the light
emitting structure; and a transparent adhesive layer disposed
between the first surface of the light emitting structure and the
transparent support substrate.
[0007] At least one of the transparent support substrate and the
transparent adhesive layer may include a wavelength conversion
material converting at least a portion of light having a first
wavelength and generated by the active layer into light having a
second wavelength. The transparent adhesive layer may have a
refractive index between a refractive index of the first
conductivity-type semiconductor layer and a refractive index of the
transparent support substrate.
[0008] The transparent adhesive layer may include at least one
material selected from the group consisting of polyacrylate,
polyimide, polyamide, and benzocyclobutene (BCB). The transparent
support substrate may be a glass substrate.
[0009] An area of the first surface of the light emitting structure
in which the concavo-convex portion is formed may be 80% or greater
of an entire area of the first surface.
[0010] According to an aspect of an example embodiment, there is
provided a semiconductor light emitting device which may include: a
light emitting structure comprising a first surface and a second
surface opposite to each other, the first surface comprising an
uneven surface; and a transparent support substrate disposed on the
first surface of the light emitting structure to structurally
support the light emitting structure, wherein the transparent
support substrate contains a wavelength conversion material
converting at least a portion of light having a first wavelength
and generated at the light emitting structure into light having a
second wavelength.
[0011] The light emitting structure may include: an n-type
semiconductor layer; a p-type semiconductor layer; an active layer
interposed between the n-type and p-type semiconductor layers to
generate light; and a buffer layer disposed on the n-type
semiconductor layer and providing the uneven surface. The buffer
layer may be formed of AlN, AlGaN or InGaN. The light emitting
structure may be a structure grown on a growth substrate which
comprises at least one of sapphire, SiC, MgAl.sub.2O.sub.4, MgO,
LiAlO.sub.2 and LiGaO.sub.2, and is replaced by the transparent
support substrate to obtain the semiconductor light emitting
device. The uneven surface is formed on the first surface of the
light emitting structure after the growth substrate is removed to
obtain the semiconductor light emitting device.
[0012] The semiconductor light emitting device may further include
an optical filter layer disposed on a surface of the transparent
support substrate and blocking light having the first wavelength
while allowing light having the second wavelength to be transmitted
therethrough.
[0013] The semiconductor light emitting device may further include
a color filter layer disposed on the optical filter layer and
allowing light partially within a wavelength band of the second
wavelength to be selectively transmitted therethrough.
[0014] The semiconductor light emitting device may further include
a light diffusion layer disposed on the color filter layer and
diffusing emitted light.
[0015] According to an aspect of an example embodiment, there is
provided a semiconductor light emitting device which may include: a
light emitting structure including a first conductivity type
semiconductor layer, an active layer, and a second conductivity
type semiconductor layer, a first through hole being formed inside
the light emitting structure; an etch stop layer disposed on a top
surface of the second conductivity type semiconductor layer of the
light emitting structure, the etch stop layer comprising a second
through hole communicating with the first through hole and used to
stop etching when the first through hole is formed; a current
spreading layer disposed on top surfaces of the second conductivity
type semiconductor layer of the light emitting structure, the
second through hole and the etch stop layer, and used to apply a
voltage to the second conductivity type semiconductor layer; a
first electrode structure on a bottom surface of the first
conductivity type semiconductor layer and electrically connected to
the first conductivity type semiconductor layer; a second electrode
structure on the bottom surface of the first conductivity type
semiconductor layer and electrically connected to the current
spreading layer through the first through hole and the second
through hole; a transparent adhesive layer on the current spreading
layer; and a transparent support substrate adhered onto the
transparent adhesive layer.
[0016] The first conductivity-type semiconductor layer may be an
n-type semiconductor layer, and the second conductivity-type
semiconductor layer may be a p-type semiconductor layer.
[0017] The semiconductor light emitting device may further include
a graded index layer disposed between the current spreading layer
and the transparent adhesive layer.
[0018] The semiconductor light emitting device may further include
a reflective layer disposed on internal surfaces of the first
through hole and the second through hole and on the bottom surface
of the first conductivity-type semiconductor layer.
BRIEF DESCRIPTION OF DRAWINGS
[0019] Example embodiments of the present inventive concept will be
more clearly understood from the following detailed description
taken in conjunction with the accompanying drawings, in which:
[0020] FIG. 1 is a cross-sectional view illustrating a
semiconductor light emitting device, according to an example
embodiment of the inventive concept;
[0021] FIG. 2 is a flow chart illustrating a method of
manufacturing a semiconductor light emitting device, according to
an example embodiment of the inventive concept;
[0022] FIG. 3 is a cross-sectional view according to an example
embodiment of the present inventive concept illustrating a
semiconductor light emitting device;
[0023] FIGS. 4A through 4F are cross-sectional views illustrating a
method of manufacturing a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0024] FIGS. 5A through 5F are cross-sectional views illustrating a
method of manufacturing a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0025] FIG. 6 is a flow chart illustrating a process of forming a
composite buffer layer, according to an example embodiment of the
inventive concept;
[0026] FIGS. 7A through 7D are cross-sectional views illustrating
various examples of a composite buffer layer of an example
embodiment of the inventive concept;
[0027] FIGS. 8 and 9 are cross-sectional views illustrating a
package including a semiconductor light emitting device, according
to an example embodiment of the inventive concept;
[0028] FIGS. 10 through 13 are cross-sectional views illustrating
semiconductor light emitting devices, according to various example
embodiments of the inventive concept;
[0029] FIG. 14 is a CIE chromaticity diagram illustrating a
wavelength conversion material of a semiconductor light emitting
device or a package, according to an example embodiment of the
inventive concept;
[0030] FIGS. 15A and 15B are cross-sectional views of a major part
of a semiconductor light emitting device, according to an example
embodiment of the inventive concept;
[0031] FIG. 15C is a bottom view of the semiconductor light
emitting device illustrated in FIG. 15A, according to an example
embodiment;
[0032] FIGS. 16A through 28A and 16B through 28B are
cross-sectional views illustrating major processes of a method of
manufacturing a semiconductor light emitting device, according to
an example embodiment of the inventive concept;
[0033] FIGS. 29 through 33 are cross-sectional views illustrating
semiconductor light emitting devices, according to various example
embodiments of the inventive concept;
[0034] FIGS. 34 and 35 are cross-sectional views schematically
illustrating white light emitting modules including a semiconductor
light emitting device, according to an example embodiment of the
inventive concept;
[0035] FIG. 36 is a perspective view schematically illustrating a
backlight unit including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0036] FIG. 37 is a view illustrating an example of a direct-type
backlight unit including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0037] FIGS. 38 and 39 are views illustrating examples of edge-type
backlight units including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0038] FIG. 40 is an exploded perspective view of a display device
including a semiconductor light emitting device, according to an
example embodiment of the inventive concept;
[0039] FIG. 41 is a perspective view of a flat-panel lighting
apparatus including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0040] FIG. 42 is an exploded perspective view of a lighting
apparatus including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0041] FIG. 43 is an exploded perspective view of a bar-type
lighting apparatus including a semiconductor light emitting device,
according to an example embodiment of the present inventive
concept;
[0042] FIG. 44 is an exploded perspective view of a lighting
apparatus including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0043] FIG. 45 is a diagram illustrating an indoor lighting control
network system including a semiconductor light emitting device,
according to an example embodiment of the inventive concept;
[0044] FIG. 46 is a diagram illustrating a network system including
a semiconductor light emitting device, according to an example
embodiment of the inventive concept;
[0045] FIG. 47 is a block diagram illustrating a communications
operation between a smart engine of a lighting apparatus including
a semiconductor light emitting device and a mobile device,
according to an example embodiment of the inventive concept;
and
[0046] FIG. 48 is a block diagram of a smart lighting system
including a semiconductor light emitting device, according to an
example embodiment of the inventive concept.
DETAILED DESCRIPTION
[0047] Hereinafter, example embodiments of the inventive concept
will be described with reference to the accompanying drawings. The
inventive concept may, however, be embodied in many different forms
and should not be construed as being limited to the example
embodiments set forth herein; rather, these example embodiments are
provided so that this disclosure will be thorough and complete, and
will fully convey the inventive concept to those of ordinary skill
in the art. It should be understood, however, that there is no
intent to limit the inventive concept to the particular forms
disclosed, but on the contrary, the inventive concept is to cover
all modifications, equivalents, and alternatives falling within the
spirit and scope of the inventive concept. In the drawings, the
dimensions of structures are exaggerated for clarity of the
inventive concept.
[0048] It will be understood that when an element, such as a layer,
a region, or a substrate, is referred to as being "on," "connected
to" or "coupled to" another element, it may be directly on,
connected or coupled to the other element or intervening elements
may be present. In contrast, when an element is referred to as
being "directly on," "directly connected to" or "directly coupled
to" another element or layer, there are no intervening elements or
layers present. Like reference numerals refer to like elements
throughout. As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items.
Expressions such as "at least one of", when preceding a list of
elements, modify the entire list of elements and do not modify the
individual elements of the list.
[0049] Also, though terms "first" and "second" are used to describe
various members, components, regions, layers, and/or portions in
various embodiments of the inventive concept, the members,
components, regions, layers, and/or portions are not limited to
these terms. These terms are used only to differentiate one member,
component, region, layer, or portion from another one. Therefore, a
member, a component, a region, a layer, or a portion referred to as
a first member, a first component, a first region, a first layer,
or a first portion in an embodiment may be referred to as a second
member, a second component, a second region, a second layer, or a
second portion in another embodiment.
[0050] Spatially relative terms, such as "above", "upper",
"beneath", "below", "lower", and the like, may be used herein for
ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. It will be understood that the spatially relative
terms are intended to encompass different orientations of the
device in use or operation in addition to the orientation depicted
in the figures. For example, if the device in the figures is turned
over, elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the exemplary term "above" may encompass both an
orientation of above and below. The device may be otherwise
oriented (rotated 90 degrees or at other orientations) and the
spatially relative descriptors used herein interpreted
accordingly.
[0051] The terminology used herein describes particular embodiments
only and the inventive concept is not limited thereby. As used
herein, the singular forms "a", "an", and "the" are intended to
include the plural forms as well, unless the context clearly
indicates otherwise. It will be understood that terms such as
"comprise", "include", and "have", when used herein, specify the
presence of stated features, integers, steps, operations, elements,
components, or combinations thereof, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, or combinations
thereof.
[0052] Hereinafter, example embodiments of the inventive concept
will be described with reference to the accompanying drawings. In
the accompanying drawings, the modifications of the illustrated
shapes may be expected according to manufacturing technologies
and/or tolerance. Therefore, the example embodiments should not be
construed as being limited to specific shapes of the illustrated
regions. The shapes may be changed during the manufacturing
processes. The following example embodiments may be combined.
[0053] The contents of the inventive concept described below may
have a variety of configurations and propose only a required
configuration herein, but are not limited thereto.
[0054] FIG. 1 is a cross-sectional view illustrating a
semiconductor light emitting device, according to an example
embodiment of the inventive concept.
[0055] A semiconductor light emitting device 50 according to an
example embodiment includes a light emitting structure 30 including
a first conductivity-type semiconductor layer 32, a second
conductivity-type semiconductor layer 37, and an active layer 35
interposed therebetween, and a transparent support substrate 71
supporting the light emitting structure 30.
[0056] The first conductivity-type semiconductor layer 32 may be a
nitride semiconductor satisfying n-type
Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x.ltoreq.1,
0.ltoreq.y.ltoreq.1, and 0.ltoreq.x+y.ltoreq.1, and an n-type
impurity may be silicon (Si). For example, the first
conductivity-type semiconductor layer 32 may be an n-type GaN. The
second conductivity-type semiconductor layer 37 may be a nitride
semiconductor layer satisfying p-type
Al.sub.xIn.sub.yGa.sub.1-x-yN, and a p-type impurity may be
magnesium (Mg). For example, the second conductivity-type
semiconductor layer 37 may be a p-type AlGaN/GaN. The active layer
35 may have a multi-quantum well (MQW) structure in which a quantum
well layer and a quantum barrier layer are alternately stacked. For
example, in a case where a nitride semiconductor is used, the
active layer 35 may have a GaN/InGaN MQW structure.
[0057] The light emitting structure 30 has first and second
surfaces respectively provided by a first conductivity-type
semiconductor layer 32 and a second conductivity-type semiconductor
layer 37. The first and second surfaces may be disposed to be
opposite to each other.
[0058] A first electrode 58 and a second electrode 59 respectively
connected to the first conductivity-type semiconductor layer 32 and
the second conductivity-type semiconductor layer 37 may be disposed
on the second surface of the light emitting structure 30. An
ohmic-contact layer 54 may be provided between the second
conductivity-type semiconductor layer 37 and the second electrode
59.
[0059] The light emitting structure 30 may have a concavo-convex
portion P formed on the first surface thereof. The concavo-convex
portion P may be formed by processing at least a portion of the
first conductivity-type semiconductor layer 32. The concavo-convex
portion P may be a protrusion having a hemispherical shape such as
in the present example embodiment, but a configuration of the
concavo-convex portion P is not limited thereto and the
concavo-convex portion P may be implemented by making the first
surface of the light emitting structure 30 uneven. The uneven
structure may take various different shapes. An area of the first
surface of the light emitting structure 30 in which the
concavo-convex portion P is formed may be 80% or greater of an
entire area of the first surface. Preferably, but not necessarily,
in order to increase light extraction efficiency, the area in which
the concavo-convex portion P is formed may be 90% or greater of the
entire area of the first surface.
[0060] The transparent support substrate 71 may be provided as a
main path along which light generated by the active layer 35 is
emitted. The transparent support substrate 71 may be formed of a
transparent material as a support substrate replacing a growth
substrate used to grow the light emitting structure 30. For
example, the transparent support substrate 71 may be a glass
substrate.
[0061] In a specific example embodiment, the transparent support
substrate 71 may be a support containing a wavelength conversion
material such as a phosphor or a quantum dot. For example, the
transparent support substrate 71 may be formed of a silicon resin
mixed with a wavelength conversion material or a transparent liquid
resin such as an epoxy resin.
[0062] In another example, in a case where the transparent support
substrate 71 is a glass substrate, a wavelength conversion material
such as a phosphor may be mixed in a glass composition, and the
mixture may be sintered at a low temperature to manufacture a
support containing the wavelength conversion material.
[0063] The transparent support substrate 71 may be adhered to the
first surface of the light emitting structure 30 using a
transparent adhesive layer 75. For example, the transparent
adhesive layer 75 may include a material selected from
polyacrylate, polyimide, polyamide, and benzocyclobutene (BCB). The
transparent adhesive layer 75 may be a layer for matching
refractive indices of the transparent support substrate 71 and the
light emitting structure 30. The refractive index of the
transparent adhesive layer 75 may be greater than that of the
transparent support substrate 71. For example, in a case where the
transparent support substrate 71 is glass having a refractive index
of about 1.5, the transparent adhesive layer 75 may have a
refractive index greater than 1.5.
[0064] Also, the refractive index of the transparent adhesive layer
75 may be lower than that of the first conductivity-type
semiconductor layer 32. For example, in a case where the first
conductivity-type semiconductor layer 32 is n-type GaN (refractive
index: about 2.3), the refractive index of the transparent adhesive
layer 75 may be 2.3 or lower.
[0065] The transparent adhesive layer 75 may be configured to act
as a wavelength conversion layer for converting a wavelength of
light generated by the active layer 35, as well as acting as a
refractive index matching layer. For example, the transparent
adhesive layer 75 may include a wavelength conversion material such
as a phosphor (please refer to FIG. 3).
[0066] FIG. 2 is a flow chart illustrating a method of
manufacturing a semiconductor light emitting device, according to
an example embodiment of the inventive concept. The manufacturing
method may be understood as being a method of manufacturing the
semiconductor light emitting device illustrated in FIG. 1.
[0067] In operation S21, a light emitting structure for a light
emitting device may be formed on a growth substrate.
[0068] The light emitting structure may include a first
conductivity-type semiconductor layer, an active layer, and a
second conductivity-type semiconductor layer, and may be a nitride
semiconductor described above. The light emitting structure may be
grown on the growth substrate using a method such as metal-organic
chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or
hydride vapor phase epitaxy (HVPE). The growth substrate may be an
insulating, conductive, or semiconductor substrate. For example,
the growth substrate may be formed of sapphire, SiC, Si,
MgAl.sub.2O.sub.4, MgO, LiAlO.sub.2, LiGaO.sub.2, or GaN.
[0069] In operation S22, a region of the first conductivity-type
semiconductor layer may be partially exposed from the light
emitting structure.
[0070] This process may be realized through an etching method of
partially removing the second conductivity-type semiconductor layer
and the active layer. The exposed region of the first
conductivity-type semiconductor layer may be provided as a region
where a first electrode is disposed.
[0071] In operation S23, a first electrode and a second electrode
may be formed on the exposed region of the first conductivity-type
semiconductor layer and on a region of the second conductivity-type
semiconductor layer, respectively.
[0072] For example, The first electrode and the second electrode
may include a material such as silver (Ag), nickel (Ni), aluminum
(Al), rhodium (Rh), palladium (Pd), iridium (Ir), ruthenium (Ru),
magnesium (Mg), zinc (Zn), platinum (Pt), gold (Au). Each of the
first electrode and the second electrode may be a single layer or
may have a structure including two or more layers. Although not
limited thereto, the first electrode and the second electrode may
be formed through a single electrode formation process, and in this
case, the same electrode material may be used.
[0073] In operation S24, a temporary substrate (or a temporary
support) may be provided on the surface of the light emitting
structure in which the first and second electrodes are formed.
[0074] Since the temporary substrate is a temporary support
structure temporarily supporting the light emitting structure in a
follow-up process, it is not required to be transparent, and thus,
supports formed of various materials may be used. The temporary
substrate may be adhered using various energy-curable joining
materials, such as a ultraviolet (UV)-cured resin, as an adhesive.
Also, the temporary substrate is removed in a follow-up process, a
temporary substrate and a joining material easy to remove and clean
may be selectively used.
[0075] In operation S25, the growth substrate is removed from the
light emitting structure.
[0076] The removing of the growth substrate may be performed
through various methods such as laser lift-off (LLO), mechanical
polishing, chemical-mechanical polishing, or chemical etching. For
example, in a case where the growth substrate is a sapphire
substrate, the LLO method may be used. In a case where the growth
substrate is a silicon substrate, mechanical or chemical-mechanical
polishing may be used.
[0077] In operation S26, a concavo-convex portion is formed on the
surface of the light emitting structure from which the growth
substrate has been removed.
[0078] A concavo-convex portion may be formed on the surface of the
light emitting structure from which the growth substrate has been
removed, in order to enhance light extraction efficiency. The
concavo-convex portion may be formed through dry etching using a
photoresist pattern. The concavo-convex portion may have various
shapes. For example, a fill factor of the concavo-convex portion
(that is, an area occupied by the concavo-convex portion in the
overall area of the corresponding surface) may be sufficiently
secured, and light extraction efficiency may be significantly
improved. For example, in the area of the first surface of the
light emitting structure 30, an area in which the concavo-convex
portion P is formed may be 80% or greater of an entire area of the
first surface. Preferably, but not necessarily, the area in which
the concavo-convex portion P is formed may be 90% or greater of the
entire area of the first surface in order to further enhance light
extraction efficiency.
[0079] In operation S27, a transparent support substrate is adhered
to the surface of the light emitting structure with the
concavo-convex portion formed thereon using a transparent adhesive
layer.
[0080] The transparent support substrate may be a support substrate
replacing the growth substrate and the temporary substrate. The
transparent support substrate is provided as a main path along
which light is emitted, and thus, it may be formed of a transparent
material. For example, the transparent support substrate may be a
glass substrate. If necessary, a thickness of the glass substrate
may be adjusted through additional polishing.
[0081] The transparent adhesive layer provided between the
transparent support substrate and the light emitting structure may
include a material selected from among polyacrylate, polyimide,
polyamide, and benzocyclobutene (BCB). As described above, the
transparent adhesive layer may have a refractive index between
those of the transparent support substrate and the light emitting
structure so as to be used as a refractive index matching layer for
enhancing light extraction efficiency. Also, the transparent
adhesive layer may be configured to act as a wavelength conversion
layer for converting a wavelength of emitted light.
[0082] In operation S28, the temporary substrate is removed from
the light emitting structure.
[0083] After the transparent support substrate is adhered, the
temporary substrate may be removed. In order to remove the
temporary substrate, various removal methods such as chemical,
mechanical, and physical (thermal shock removal for example) may be
used. In a case where a curable resin layer is used to adhere the
temporary substrate, a cleaning process may be additionally
performed to remove the curable resin layer and clean a surface of
an electrode.
[0084] The above method of the present example embodiment may be
applied to a process of manufacturing various types of
semiconductor light emitting devices. For example, a process of
manufacturing a nitride semiconductor light emitting device using a
silicon substrate may be advantageously applied to the present
example embodiment.
[0085] FIG. 3 is a cross-sectional view illustrating a
semiconductor light emitting device, according to an example
embodiment of the inventive concept.
[0086] A semiconductor light emitting device 100 according to the
present example embodiment includes a light emitting structure 130
including a first conductivity-type semiconductor layer 132, a
second conductivity-type semiconductor layer 137, and an active
layer 135 interposed therebetween, and a transparent support
substrate 171 supporting the light emitting structure 130.
[0087] A first conductivity-type semiconductor layer 132 and a
second conductivity-type semiconductor layer 137 and the active
layer 135 may be nitride semiconductors described above with
reference to FIG. 1. The light emitting structure 130 has first and
second surfaces respectively provided by the first
conductivity-type semiconductor layer 132 and the second
conductivity-type semiconductor layer 137.
[0088] A hole penetrating through the second conductivity-type
semiconductor layer 137 and the active layer 135 to reach a region
of the first conductivity-type semiconductor layer 132 is formed on
the second surface of the light emitting structure 130. The hole
may have a circular or hexagonal shape when viewed from above or in
a plan view, or may extend to have a groove shape as necessary. A
first electrode E1 is disposed in the hole and connected to the
first conductivity-type semiconductor layer 132.
[0089] A second electrode E2 may be disposed on the top surface of
the second conductivity-type semiconductor layer 137. The second
electrode E2 may include an ohmic-contact layer 154 and a second
conductive layer 156b. The second conductive layer 156b may be
formed of the same material as that of a first conductive layer
156a of the first electrode E1. For example, the two conductive
layers 156a and 156b may include a material such as Ag, Ni, Al, Rh,
Pd, Ir, Ru, Mg, Zn, Pt, or Au. Each of the two conductive layers
156a and 156b may be a single layer or may have a structure
including two or more layers. The first conductive layer 156a and
the second conductive layer 156b may be formed through a single
electrode formation process, and in this case, the same electrode
material may be used. An example of the process may be understood
with reference to FIGS. 4C through 4F.
[0090] An insulating layer 140 specifying first and second contact
areas C1 and C2 for electrode formation may be formed on the second
surface of the light emitting structure 130. The insulating layer
140 may include first and second insulating layers 141 and 143. The
first insulating layer 141 may be formed to open the first and
second contact areas C1 and C2, and the second insulating layer 143
may be formed to open the first contact area C1 and cover the
second contact area C2.
[0091] A portion of the first electrode E1 may extend to the top
surface of the insulating layer 140, and may overlap the second
electrode E2 with the insulating layer 140 interposed therebetween.
First and second solder pads 158 and 159 may be formed on the
overlapping portion of the first electrode E1 and an exposed
portion of the second electrode E2, respectively. An additional
insulating layer 147 has openings for forming the first and second
solder pads 158 and 159. The first and second solder pads 158 and
159 may include under bump metallurgy (UBM).
[0092] The light emitting structure 130 may have a concavo-convex
portion P formed on the first surface thereof. In the present
example embodiment, a cross-section of the concavo-convex portion P
may have a triangular protrusion (for example, a hexagonal
pyramid), or may have various other shapes as necessary. The
concavo-convex portion P may be formed by processing a surface of
the first conductivity-type semiconductor layer 132. According to
an example embodiment, at least a portion of a buffer layer 110
(please refer to FIG. 4A) used when the light emitting structure
130 is grown may be formed as a concavo-convex portion P. An area
of the first surface of the light emitting structure 130 in which
the concavo-convex portion P is formed may be 80% or greater of an
entire area of the first surface. Preferably, but not necessarily,
in order to increase light extraction efficiency, the area in which
the concavo-convex portion P is formed may be 90% or greater of the
entire area of the first surface.
[0093] The transparent support substrate 171 may be provided as a
main path along which light generated by the active layer 135 is
emitted. The transparent support substrate 171 may be formed of a
transparent material as a support substrate replacing a growth
substrate used to grow the light emitting structure 130. For
example, the transparent support substrate 171 may be a glass
substrate.
[0094] The transparent support substrate 171 may be adhered to the
first surface of the light emitting structure 130 using a
transparent adhesive layer 175. For example, the transparent
adhesive layer 175 may include a material selected from
polyacrylate, polyimide, polyamide, and benzocyclobutene (BCB). The
transparent adhesive layer 175 may be a layer for matching
refractive indices of the transparent support substrate 171 and the
light emitting structure 130. The refractive index of the
transparent adhesive layer 175 may be between a refractive index of
the transparent support substrate 171 and a refractive index of the
first conductivity-type semiconductor layer 132. For example, in a
case where the transparent support substrate 171 is glass having a
refractive index of about 1.5, the transparent adhesive layer 175
may be formed of a material having a refractive index greater than
1.5 and smaller than 2.3.
[0095] The transparent adhesive layer 175 may include a wavelength
conversion material 174 such as a phosphor. For example, the
transparent adhesive layer 175 may be formed of a BCB material in
which red and green phosphors are dispersed. In such a structure, a
process of forming a wavelength conversion unit may be omitted or
simplified.
[0096] Using the transparent adhesive layer 175, the transparent
support substrate 171 may be easily adhered to the surface with the
concavo-convex portion formed thereon, and light extraction
efficiency of the device 100 may be enhanced through refractive
index matching using the refractive index of the transparent
adhesive layer 175. In addition, since the transparent adhesive
layer 175 contains the wavelength conversion material 174, an
additional wavelength conversion unit formation process may be
simplified.
[0097] FIGS. 4 and 5 are cross-sectional views illustrating major
processes of a method of manufacturing a semiconductor light
emitting device, according to an example embodiment of the
inventive concept. The manufacturing method may be divided into a
device manufacturing process (FIGS. 4A through 4F) and a substrate
replacing process (FIGS. 5A through 5F).
[0098] Referring to FIG. 4A, a buffer layer 110 is formed on a
growth substrate 101, and a light emitting structure 130 for a
light emitting device may be formed on the buffer layer 110. The
light emitting structure 130 may include a first conductivity-type
semiconductor layer 132, an active layer 135, and a second
conductivity-type semiconductor layer 137.
[0099] The buffer layer 110 may include
In.sub.xAl.sub.yGa.sub.1-x-yN, where 0.ltoreq.x.ltoreq.1 and
0.ltoreq.y.ltoreq.1. For example, the buffer layer 110 may be
formed of AlN, AlGaN or InGaN. If necessary, a plurality of layers
may be combined to be used as a buffer layer or a material
composition in the buffer layer may be gradually changed. When the
growth substrate is a silicon substrate and a nitride semiconductor
layer is grown as a light emitting structure, the buffer layer may
have various types of composite buffer structure. This will be
described in detail with reference to FIGS. 6 and 7.
[0100] Each layer of the light emitting structure 130 may be a
nitride semiconductor described above in the previous example
embodiment, and may be grown on a growth substrate 101 using a
method such as MOCVD, MBE, or HYPE.
[0101] Subsequently, as illustrated in FIG. 4B, a hole H partially
exposing a region of the first conductivity-type semiconductor
layer 132 may be formed in the light emitting structure 130.
[0102] This process may be realized by an etching method of
partially removing regions of the second conductivity-type
semiconductor layer 137 and the active layer 135. The region of the
first conductivity-type semiconductor layer 132 exposed by the hole
H may be provided as a region where a first electrode is
formed.
[0103] Thereafter, a first electrode E1 and a second electrode E2
may be formed to be connected to a region of the first
conductivity-type semiconductor layer 132 and a region of the
second conductivity-type semiconductor layer 137, respectively.
[0104] In the present example embodiment, the electrode formation
process may be realized through the process illustrated in FIGS. 4C
through 4F.
[0105] First, as illustrated in FIG. 4C, an ohmic-contact layer 154
may be formed on the top surface of the second conductivity-type
semiconductor layer 137.
[0106] This process may be realized by forming a first insulating
layer 141 on the entire top surface of the light emitting structure
130, allowing a region in which the ohmic-contact layer 154 is to
be formed to be exposed using a mask, and subsequently depositing
the ohmic-contact layer 154 on the exposed region.
[0107] The first insulating layer 141 may be formed of SiO.sub.2,
Si.sub.3N.sub.4, HfO.sub.2, SiON, TiO.sub.2, Ta.sub.2O.sub.3, or
SnO.sub.2. As described above, the insulating layer 141 may be a
distributed Bragg reflector (DBR) multilayer formed by alternately
stacking dielectric layers having different refractive indices.
[0108] The ohmic-contact layer 154 may include a highly reflective
ohmic contact material forming ohmic-contact with the second
conductivity-type semiconductor layer 137 and having high
reflectivity. For example, the ohmic-contact layer 154 may include
silver (Ag) or Ag/Ni. The ohmic-contact layer 154 may further
include a barrier layer. For example, the barrier layer may be
formed of titanium (Ti) or Ni/Ti. The barrier layer may prevent a
partial component of a solder bump formed in a follow-up process
from being spread, whereby ohmic characteristics of the
ohmic-contact layer 154 may be maintained.
[0109] Thereafter, as illustrated in FIG. 4D, a second insulating
layer 143 having first opening O1 and a second opening O2 may be
formed on the top surface of the light emitting structure 130.
[0110] The first opening O1 and the second opening O2 may be formed
to open an exposed region of the first conductivity-type
semiconductor layer 132 and a region of the second electrode 154,
respectively. In forming the first opening O1 and the second
opening O2, a first insulating layer 141 may be formed using a mask
for forming the first opening O1 and the second opening O2 after an
insulating material is formed on the entire top surface. The first
opening O1 and the second opening O2 may define a contact region
for a first electrode and a second electrode, respectively. The
second insulating layer 143 may be formed to cover the
ohmic-contact layer 154 disposed on a partial mesa region
(indicated by "A"). The second insulating layer 143 may be
understood as an insulating layer 140 for passivation with the
first insulating layer 141. The second insulating layer 143 may be
formed of the same material as that of the first insulating layer
141.
[0111] Thereafter, as illustrated in FIG. 4E, first and second
conductive layers 156a and 156b may be formed to be connected to
open regions of the first opening O1 and the second opening O2,
respectively.
[0112] The first conductive layer 156a may be provided as a first
electrode E1, and the second conductive layer 156b, together with
the ohmic-contact layer 154, may be provided as a second electrode
E2. This process may be performed by forming a conductive layer on
the insulating layer 140 to cover the open regions of the first
opening O1 and the second opening O2 and dividing the conductive
layer in a specific region S to be first and second regions
respectively connected to the open regions of the first opening O1
and the second opening O2. Here, the first and second regions of
the conductive layer may be a first conductive layer 156a and a
second conductive layer 156b, respectively. For example, the first
conductive layer 156a and the second conductive layer 156b may each
include a material such as Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt,
or Au, and may be a single layer or may have a structure including
two or more layers. In a mesa region A in which the ohmic-contact
layer 154 is covered by the second insulating layer 143, a portion
of the first conductive layer 156a may extend to the top surface of
the insulating layer 140 and may overlap the second electrode E2
with the insulating layer 140 interposed therebetween.
[0113] In addition, as illustrated in FIG. 4F, first and second
solder pads 158 and 159 may be partially formed in a region of the
first electrode E1 and partially formed in a region of the second
electrode E2.
[0114] The first solder bump 158 may be partially disposed in a
region of the first electrode E1 disposed on the mesa region A. In
the mesa region A, the ohmic-contact layer 154 is covered by the
second insulating layer 143 and a portion of the first electrode E1
may extend to the region.
[0115] The first and second solder pads 158 and 159 may include a
UBM layer. For example, the first and second solder pads 158 and
159 may be multilayer structures including a titanium (Ti) film and
a nickel (Ni) film disposed on the Ti film. If necessary, a copper
(Cu) film may be used instead of the Ni film. In another example,
the first and second solder pads 158 and 159 may be multilayered
structures of Cr/Ni films or Cr/Cu films.
[0116] FIGS. 5A through 5F are cross-sectional views illustrating a
method of manufacturing a semiconductor light emitting device,
according to an example embodiment of the inventive concept. In
these processes, the growth substrate of the previously obtained
semiconductor light emitting device may be replaced with a
transparent support substrate.
[0117] Referring to FIG. 5A, a temporary support 160 may be
provided on the second surface of the light emitting structure 130,
that is, the surface on which the first electrode E1 and the second
electrode E2 are formed.
[0118] The temporary support 160 may include a temporary substrate
161 and a temporary adhesive layer 165 for adhering the temporary
substrate 161. For example, the temporary substrate 161 may be a
quartz substrate. The temporary substrate 161 may be adhered using
the temporary adhesive layer 165 such as various energy-cured
resins including a UV-cured resin. Also, the temporary substrate
161 and the temporary adhesive layer 165 may be formed of a
material that can easily be removed and cleaned in a follow-up
process.
[0119] Thereafter, as illustrated in FIG. 5B, the growth substrate
101 may be removed from the light emitting structure 130.
[0120] The growth substrate 101 may be removed through various
methods such as such as laser lift-off (LLO), mechanical polishing,
chemical-mechanical polishing, or chemical etching. In a case where
the growth substrate 101 is a silicon substrate, since mechanical
strength thereof is relatively low, mechanical or
chemical-mechanical polishing may be used.
[0121] In the present example embodiment, a configuration in which
the buffer layer 110 remains is illustrated, but the inventive
concept is not limited thereto and at least a portion of the buffer
layer 110 may be removed together as necessary.
[0122] Thereafter, as illustrated in FIG. 5C, a concavo-convex
portion P may be formed on the first surface of the light emitting
structure 130, that is, on the surface from which the growth
substrate 101 has been removed.
[0123] The concavo-convex portion P may be formed directly on the
surface of the light emitting structure 130 (specifically, on the
surface of the first conductivity-type semiconductor layer 132) in
order to enhance light extraction efficiency. The concavo-convex
portion P may be formed through dry etching using a photoresist
pattern. In the course of forming the concavo-convex portion P, a
thickness t1 corresponding to the second conductivity-type
semiconductor layer 137 and the buffer layer 110 may be reduced to
a desired thickness t2. In another example, at least a portion of
the concavo-convex portion P may be formed as the buffer layer 110
by lowering an etching depth.
[0124] As described above, in this process, since there is no need
to form a plane between protrusions and depressions of the
concavo-convex portion P, a fill factor of the concavo-convex
portion P (that is, an area occupied by the concavo-convex portion
P in the overall area of the corresponding surface) may be
sufficiently secured, and as a result, light extraction efficiency
of the device may be significantly improved. For example, in the
area of the first surface of the light emitting structure 130, an
area in which the concavo-convex portion P is formed may be 80% or
greater of an entire area of the first surface, and preferably, but
not necessarily, 90% or greater of the entire area of the first
surface.
[0125] Thereafter, as illustrated in FIG. 5D, a transparent support
substrate 171 may be adhered to the first surface of the light
emitting structure 130, that is, the surface on which the
concavo-convex portion P is formed, using the transparent adhesive
layer 175.
[0126] The transparent support substrate 171 may be a permanent
support substrate replacing the growth substrate and the temporary
substrate. Since the transparent support substrate 171 is provided
as a main path along which light is emitted, the transparent
support substrate 171 may be formed of a transparent material. For
example, the transparent support substrate 171 may be a glass
substrate. The transparent adhesive layer 175 may include an
adhesive material having transparency. As described above, the
transparent adhesive layer 175 may have a refractive index between
those of the transparent support substrate 171 and the light
emitting structure 130 so as to be used as a refractive index
matching layer for enhancing light extraction efficiency. Also, the
transparent adhesive layer 175 may include a wavelength conversion
material 174 for converting a wavelength of emitted light to serve
as a wavelength conversion unit.
[0127] If necessary, as illustrated in FIG. 5E, the transparent
support layer 171 may be polished such that a thickness to thereof
is reduced to a desired thickness tb. Through this process, a
desired thickness of a final semiconductor light emitting device
may be determined.
[0128] Thereafter, as illustrated in FIG. 5F, the temporary support
160 may be removed from the light emitting structure 130. This
process may be performed such that the temporary substrate 161 is
removed and the temporary adhesive layer 165 is subsequently
removed using a cleaning method.
[0129] According to the present example embodiment, the transparent
adhesive layer is introduced between the transparent support
substrate and the light emitting structure and the transparent
support substrate may be provided on the surface of the light
emitting structure on which the concavo-convex portion is formed.
The transparent adhesive layer may be utilized as a wavelength
conversion structure, as well as as a reflective index matching
layer.
[0130] <Evaluation of Fill Factor of Concavo-Convex
Portion>
[0131] A semiconductor light emitting device was manufactured to
have a structure similar to that illustrated in FIG. 3, but under
conditions in which a wavelength conversion material was not
present (Embodiment 1). For comparison, a semiconductor light
emitting device having a structure similar to that illustrated in
FIG. 3 was manufactured using a growth substrate with a
concavo-convex portion formed on a surface thereof (Comparative
Example 1).
[0132] Both Embodiment 1 and Comparative Example 1 commonly include
a concavo-convex portion formed at an interface between a light
emitting structure and a substrate. However, in the semiconductor
light emitting device according to Comparative Example 1, the
concavo-convex portion was formed on the growth substrate, and
thus, there are limitations in increasing a fill factor of the
concavo-convex portion for crystal growth. As a result, a fill
factor of the concavo-convex portion employed in Comparative
Example 1 was 58%. In contrast, in the semiconductor light emitting
device according to Embodiment 1, the concavo-convex portion was
formed on the light emitting structure (specifically, on the
surface of the first conductivity-type semiconductor layer) after
the growth substrate was removed, and thus, a fill factor of the
concavo-convex portion may be increased to 91%.
[0133] In order to confirm the effect based on the difference
between the fill factors of the concavo-convex portions, optical
outputs of the semiconductor light emitting devices according to
Embodiment 1 and Comparative Example 1 and optical outputs of
semiconductor light emitting device packages having the same
structure were measured and are illustrated in Table 1.
TABLE-US-00001 TABLE 1 Optical Output Optical Output Fill Factor of
of of Concavo- Semiconductor Semiconductor convex Light Emitting
Light Emitting Classification Portion Device Device Package
Embodiment 0.91 102.7% 105% Comparative 0.58 100% 100% Example
(Reference)
[0134] As illustrated in Table 1, it can be seen that the optical
output of Embodiment 1 in which a fill factor of the concavo-convex
portion can be increased is 2.7% and 5% greater than that of
Comparative Example 1 in the device level and the package level,
respectively. In general, when the fill factor of the
concavo-convex portion is 80% or greater, light extraction
efficiency may be significantly improved.
[0135] Hereinafter, a buffer layer used when a light emitting
structure is grown with a nitride semiconductor on a silicon
substrate as in the previous example embodiment will be
described.
[0136] As illustrated in FIG. 6, an operation of forming a buffer
layer on a silicon substrate includes operation S181 of forming a
nucleation layer and operation S183 of forming a lattice buffer
layer on the nucleation layer.
[0137] The operation of forming a buffer layer according to the
present example embodiment may start with operation S181 of forming
the nucleation layer on a silicon substrate.
[0138] The nucleation layer may be formed on the (111) plane of the
silicon substrate. The nucleation layer may provide a growth
surface with improved wettability. For example, the nucleation
layer may be AlN. For example, the nucleation layer may have a size
of tens to hundreds of nm.
[0139] In operation S183, a lattice buffer layer may be formed on
the nucleation layer. The lattice buffer layer may form a
dislocation loop at an interface between the lattice buffer layer
and a nitride crystal to be grown in a follow-up process to reduce
dislocation density. Also, the lattice buffer layer may alleviate
lattice mismatches and mismatches of coefficients of thermal
expansion between the lattice buffer layer and a nitride single
crystal to be grown in a follow-up process to effectively generate
compressive stress when a crystal is grown and reduce tensile
stress generated during cooling. The lattice buffer layer may be
formed of a nitride crystal containing aluminum (Al) and may be a
single layer or multiple layers. For example, the lattice buffer
layer may be a graded Al.sub.xIn.sub.yGa.sub.1-x-yN, where
0.ltoreq.x, y.ltoreq.1, x+y.ltoreq.1 or
Al.sub.x1In.sub.y1Ga.sub.1-x1-y1N/Al.sub.x2In.sub.y2Ga.sub.1-x2-y2N,
where 0.ltoreq.x1, x2, y1, y2.ltoreq.1, x1.noteq.x2, or
y1.noteq.y2, x1+y1.ltoreq.1, x2+y2.ltoreq.1 superlattice layer in
which the content of a partial component such as AlGaN or Al is
increased or decreased linearly or stepwise. In a specific example,
the lattice buffer layer may have a structure in which AlGaN and
AlN are alternately stacked. For example, the lattice buffer layer
may have a triple-layer structure of AlGaN/AlN/AlGaN.
[0140] Thereafter, the operation of forming the nitride single
crystal may include operations S184, S186, and S188 of sequentially
forming a first nitride semiconductor layer, an intermediate layer,
and a second nitride semiconductor layer on the lattice buffering
layer.
[0141] The operation of forming the nitride single crystal may
start with operation S184 of forming the first nitride
semiconductor layer on the lattice buffering layer.
[0142] The first nitride semiconductor layer may be a nitride
crystal having a lattice constant greater than that of the lattice
buffering layer. The first nitride semiconductor layer may include
Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x, y.ltoreq.1 and
x+y<1. For example, the first nitride semiconductor layer may be
GaN.
[0143] The first nitride semiconductor layer may receive
compressive stress in an interface between the first nitride
semiconductor layer and the lattice buffering layer, and when the
first nitride semiconductor layer is cooled to a room temperature
after completion of the growth process, tensile stress may occur
due to a difference in coefficients of thermal expansion between
the substrate and the first nitride semiconductor layer. In order
to compensate for the stress, in operation S186, the intermediate
layer may be formed on the first nitride semiconductor layer. The
intermediate layer may be a nitride crystal having a lattice
constant smaller than that of the first nitride semiconductor
layer. For example, the intermediate layer may be
Al.sub.xGa.sub.1-xN, where 0.4<x<1.
[0144] Thereafter, in operation S188, a second nitride
semiconductor layer may be formed on the intermediate layer. The
second nitride semiconductor layer may have high compressive
stress. Relatively weak compressive stress or tensile stress acting
on the first nitride semiconductor layer may be compensated for by
compressive stress of the second nitride semiconductor layer to
reduce cracking. Similar to the first nitride semiconductor layer,
the second nitride semiconductor layer may include
Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x, y.ltoreq.1 and
x+y<1. For example, the second nitride semiconductor layer may
be GaN. GaN used as the first and second nitride semiconductor
layers may be undoped GaN.
[0145] In a specific example embodiment, a nitride stacked body
having at least one nitride semiconductor layer may additionally be
formed on the second nitride semiconductor layer. Such a nitride
semiconductor layer may be formed as Al.sub.xIn.sub.yGa.sub.1-x-yN,
where 0.ltoreq.x, y.ltoreq.1, x+y1, and may be an undoped layer or
a layer doped with an n-type and/or a p-type impurity. For example,
the nitride semiconductor layer may be a plurality of semiconductor
layers provided as a device for performing a specific function.
[0146] FIGS. 7A through 7D are cross-sectional views illustrating
various examples of structures of a buffer layer and a stress
compensation layer that are usable for an example embodiment of the
inventive concept. An additional stress compensation layer
structure may also be introduced to the example embodiment
illustrated in FIGS. 3 and 4A, in addition to the buffer layer
110.
[0147] As illustrated in FIG. 7A, a buffer layer 210, a stress
compensation layer 220, and a nitride stacked body 230 may be
sequentially disposed on a silicon substrate 201.
[0148] The silicon substrate 201 may include a substrate partially
including a silicon material, as well as a substrate formed of only
a silicon material. For example, a silicon-on insulator (SOI)
substrate may be used. The top surface of the silicon substrate 201
may be the (111) plane. The buffer layer 210 may include a
nucleation layer 212 disposed on the silicon substrate 201 and the
lattice buffering layer 214 disposed on the nucleation layer
212.
[0149] The nucleation layer 212 may be formed of AlN. The lattice
buffering layer 214 may bend threading dislocation to reduce a
defect. As a thickness of the lattice buffering layer 214 is
increased, compressive stress relaxation in a first nitride
semiconductor layer 221 to be grown in a follow-up process may be
reduced and a defect rate may also be reduced. The thickness of the
lattice buffering layer 214 may range from hundreds of nm to a few
nm.
[0150] The lattice buffering layer 214 may have a single
composition, or as illustrated in FIG. 4A, the lattice buffering
layer 214 may be a graded layer of Al.sub.xIn.sub.yGa.sub.1-x-yN,
where 0.ltoreq.x, y.ltoreq.1 and x+y1. The graded structure
employed in the present example embodiment includes a plurality of
layers 214-1, 214-2, . . . , 214-n, and the plurality of layers
214-1, 214-2, . . . , 214-n may have a step-graded structure in
which an aluminum (Al) composition is reduced in a stepwise manner.
In a specific example, the lattice buffering layer 214 having a
graded structure may be realized as a three-component system AlGaN
in which the Al composition is adjusted. In another example, the
lattice buffering layer 214 may have a linearly graded structure,
rather than step-graded structure.
[0151] The lattice buffering layer 214 may reduce a lattice
mismatch between the AlN nucleation layer 212 and the first nitride
semiconductor layer 221 in a stepwise manner. In particular, when a
crystal is grown, the lattice buffering layer 214 may effectively
generate compressive stress to reduce tensile stress generated
during cooling.
[0152] The stress compensation layer 220 may include a first
nitride semiconductor layer 221, an intermediate layer 222, and a
second nitride semiconductor layer 223 sequentially disposed on the
lattice buffering layer 214.
[0153] The first nitride semiconductor layer 221 may be a nitride
crystal having a lattice constant greater than that of the lattice
buffering layer 223. The first nitride semiconductor layer 221 may
include Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x, y.ltoreq.1
and x+y<1, and may be, for example, GaN. The first nitride
semiconductor layer 221 may receive compressive stress in an
interface between the first nitride semiconductor layer 221 and the
lattice buffering layer 214.
[0154] Such compressive stress may be reduced as a thickness of the
first nitride semiconductor layer 221 is increased. In a case where
the thickness (about 2 .mu.m) of the first nitride semiconductor
layer 221 is increased, when the growth process is completed and
cooling is performed to a room temperature, it is difficult to
control tensile stress occurring due to a difference in
coefficients of thermal expansion between the substrate 201 and the
first nitride semiconductor layer 221 and cracking may occur.
[0155] The intermediate layer 222 may be disposed on the first
nitride semiconductor layer 221 in order to compensate for tensile
stress occurring during cooling. The intermediate layer 222 may be
a nitride crystal having a lattice constant smaller than that of
the first nitride semiconductor layer 221. For example, the
intermediate layer 222 may be Al.sub.xGa.sub.1-xN, where
0.4<x<1.
[0156] The second nitride semiconductor layer 223 may be disposed
on the intermediate layer 222. The second nitride semiconductor
layer 223 may have compressive stress. The compressive stress of
the second nitride semiconductor layer 223 may compensate for
relatively weak compressive stress or tensile stress acting on the
first nitride semiconductor layer 221, suppressing the occurrence
of cracks. Similar to the first nitride semiconductor layer 221,
the second nitride semiconductor layer 223 may include
Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x, y.ltoreq.1 and
x+y<1. For example, the second nitride semiconductor layer 223
may be formed of GaN. At least one of the first and second nitride
semiconductor layers 221 and 223 may be, but is not limited to, an
undoped nitride layer.
[0157] The nitride stacked body 230 may correspond to the light
emitting structure 30 or 130 of the previous example embodiment
described above.
[0158] Referring to FIG. 7B, similar to the example of FIG. 7A, a
buffer layer 210, a stress compensation layer 220, and a nitride
stacked body 230 are sequentially disposed on a silicon substrate
201.
[0159] The components denoted by the same reference numerals as
those of FIG. 7A may be referred to in descriptions of FIG. 7A and
combined with descriptions of the present example embodiment,
unless otherwise mentioned.
[0160] Similarly to the buffer layer 210 illustrated in FIG. 7A,
the buffer layer 210 includes an AlN nucleation layer 212 and a
lattice buffering layer 214'. The lattice buffering layer 214' used
in the present example embodiment has a structure different from
that of the lattice buffering layer 214 illustrated in FIG. 4A.
[0161] The lattice buffering layer 214' may have a superlattice
structure in which two or more layers 214a and 214b having
different compositions are alternately stacked. For example, the
lattice buffering layer 214' may be a
Al.sub.x1In.sub.y1Ga.sub.1-x1-y1/N/Al.sub.x2In.sub.y2Ga.sub.1-x2-
-y2N, where 0.ltoreq.x1, x2, y1, y2.ltoreq.1, and x1.noteq.x2 or
y1.noteq.y2, x1+y1.ltoreq.1, and x2+y2.ltoreq.1, superlattice
layer. As in the present example embodiment, the lattice buffering
layer 214' adopting the superlattice structure may effectively
reduce stress between the silicon substrate 201 and the first
nitride semiconductor layer 221.
[0162] The stress compensation layer 220 employed in the present
example embodiment may include first and second nitride
semiconductor layers 221 and 223, a first intermediate layer 222
disposed between the first and second nitride semiconductor layers
221 and 223, a second intermediate layer 224, and a third nitride
semiconductor layer 225.
[0163] The second intermediate layer 224 and the third nitride
semiconductor layer 225 may be understood as performing a function
similar to those of the first intermediate layer 222 and the second
nitride semiconductor layer 223. That is, the second intermediate
layer 224 may be disposed on the second nitride semiconductor layer
223 in order to compensate for tensile stress generated during
cooling. The second intermediate layer 224 may be a nitride crystal
having a lattice constant smaller than that of the second nitride
semiconductor layer 223. For example, the second intermediate layer
224 may be Al.sub.xGa.sub.1-xN, where 0.4<x<1, similar to the
first intermediate layer 222.
[0164] The third nitride semiconductor layer 225 may be disposed on
the second intermediate layer 224. The third nitride semiconductor
layer 225 may have compressive stress, and the compressive stress
of the third nitride semiconductor layer 225 may compensate for
relatively weak compressive stress or tensile stress acting on the
first and second nitride semiconductor layers 221 and 223 (in
particular, 223) disposed therebelow, to suppress the occurrence of
cracks.
[0165] Similar to the second nitride semiconductor layer 223, the
third nitride semiconductor layer 225 may include
Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x, y.ltoreq.1 and
x+y<1. For example, the third nitride semiconductor layer 225
may be GaN.
[0166] Referring to FIG. 7C, similar to the example of FIG. 7A, a
buffer layer 210, a stress compensation layer 220, and a nitride
stacked body 230 are sequentially disposed on a silicon substrate
201. However, unlike the example of FIG. 7A, a mask layer 226 and a
coalesced nitride layer 227 formed on the mask layer 226 are
included.
[0167] The mask layer 226 may be disposed on the first nitride
semiconductor layer 221.
[0168] Most of the threading dislocations from the first nitride
semiconductor layer 221 are blocked by the mask layer 226, and the
other remaining threading dislocation may be bent by the
coalescence nitride layer 227 grown in a follow-up process. As a
result, defect density of a nitride crystal grown in a follow-up
process may be significantly improved. A thickness and defect
density of the coalescence nitride layer 227 may vary according to
growth conditions, for example, variables such as a temperature,
pressure, and a mole ratio of a V/III source.
[0169] The mask layer 226 may be formed of a silicon nitride
(SiN.sub.x) or a titanium nitride (TiN). For example, a SiN.sub.x
mask layer 226 may be formed using silane (SiH.sub.4) and an
ammonia gas. The mask layer 226 may not completely cover a surface
of the first nitride semiconductor layer 221. Thus, an exposed
region of the first nitride semiconductor layer 221 may be
determined according to a degree to which the mask layer 226 covers
the first nitride semiconductor layer 221, and an initial island
growth shape of a nitride crystal grown thereon may be varied. For
example, in a case where the exposed area of the nitride
semiconductor layer is reduced by increasing the mask region of
SiN.sub.x, density of an initial island of the nitride layer 227 to
be grown on the mask layer 226 may be reduced, while a size of a
relatively coalesced island may be increased. Thus, a thickness of
the coalesced nitride layer 227 may also be increased.
[0170] In a case where the mask layer 226 is added, stress between
the first and second nitride semiconductor layers 221, 223 may be
decoupled by the mask layer 226, and thus, compressive stress
transferred to the coalesced nitride layer 227 may be partially
blocked. Also, relative tensile stress may occur in the coalesced
nitride layer 227 while grown islands coalesce. As a result, the
first nitride semiconductor layer 221 may receive strong
compressive stress by the buffer layer 210, while the coalesced
nitride layer 227 on the mask layer 226 may receive relatively weak
compressive stress or tensile stress due to stress decoupling and
island coalescence. When a thickness of the layer having a
relatively small compressive stress exceeds a threshold point,
cracks do not occur in a thin film during cooling, and thus, a
thickness of the coalesced nitride layer 227 may be selected under
the conditions in which cracks do not occur and defect density is
reduced.
[0171] Referring to FIG. 7D, a buffer layer 210, a stress
compensation layer 220, and a nitride stacked body 230 are
sequentially disposed on a silicon substrate 201.
[0172] The stress compensation layer 220 employed in the present
example embodiment may include first and second nitride
semiconductor layers 220a and 220b formed under different growth
conditions. The first nitride semiconductor layer 220a may be grown
in a two-dimensional (2D) mode such that an increase in surface
roughness is controlled, to thereby reduce occurrence of a twist
grain boundary in an interface between the first nitride
semiconductor layer 220a and the second nitride semiconductor layer
220b.
[0173] The first nitride semiconductor layer 220a may be formed
under a first growth condition to have surface roughness equal to
3% or less of surface roughness of the buffer layer 210, and the
second nitride semiconductor layer 220b may be formed on the first
nitride semiconductor layer 220a under a second growth condition.
Here, at least one of a temperature, pressure, and a V/III group
mole ratio of the second growth condition may be different from
those of the first growth condition such that a three-dimensional
(3D) growth mode is increased in the second growth condition,
compared with the first growth condition. The first nitride
semiconductor layer 220a may have a thickness ranging from 2 nm to
1000 nm. As the thickness of the first nitride semiconductor layer
220a is increased, occurrence of the twist grain boundary may be
reduced in the interface between the first nitride semiconductor
layer 220a and the second nitride semiconductor layer 220b. Here,
however, if the first nitride semiconductor layer 220a is too
thick, crystallinity of an overall thin film may be degraded. In
this regard, since the first nitride semiconductor layer 220a is
grown at a temperature lower than that of the nitride layer, a
defect rate may be rather increased. Thus, it would be desirable to
reduce occurrence of the twist grain boundary, while the thickness
of the first nitride semiconductor layer 220b is reduced.
[0174] When the twist grain boundary is reduced, a defect of the
second nitride semiconductor layer 220b stacked on the first
nitride semiconductor layer 220a may be reduced. That is, since the
first nitride semiconductor layer 220a has a thickness ranging from
2 nm to 1000 nm and has roughness of 3% or less of that of the
buffer layer 210, a defect of the second nitride semiconductor
layer 220b stacked thereon may be reduced. Thus, the same
crystallinity may be obtained from a reduced thickness, making the
entire structure thinner (reduced in thickness). For example, even
though a mask layer is not used, an overall thickness of the buffer
layer 210 and the stress compensation layer 220 may be manufactured
to be 6 .mu.m or less. Thus, a process time of the crystal growth
process and manufacturing costs may be reduced.
[0175] The second nitride semiconductor layer 220b may be formed of
Al.sub.xIn.sub.yGa.sub.1-x-yN, where 0.ltoreq.x, y.ltoreq.1 and
x+y<1. The second nitride semiconductor layer 220b may be
continuously grown on the first nitride semiconductor layer 220a
without additionally growing any intervening layer of a different
composition. The second nitride semiconductor layer 220b may have
the same composition as that of the first nitride semiconductor
layer 220a. For example, the first and second nitride semiconductor
layers 220a and 220b may be GaN. In a specific example, the first
nitride semiconductor layer 220a may be undoped GaN, and the second
nitride semiconductor layer 220b may be n-type GaN.
[0176] The semiconductor light emitting device illustrated in FIG.
3 may be used in a semiconductor light emitting device package
(FIGS. 8 and 9). In this case, a wavelength conversion unit having
various shapes may be additionally provided.
[0177] FIG. 8 is a cross-sectional view of a semiconductor light
emitting device package, according to an example embodiment of the
inventive concept.
[0178] Referring to FIG. 8, a semiconductor light emitting device
package 340 according to the present example embodiment includes a
package board 310 having a mounting surface and a semiconductor
light emitting device 50 mounted on the mounting surface of the
package board 310.
[0179] The package board 310 may include first and second wiring
electrodes 312a and 312b disposed on the mounting surface. The
first and second wiring electrodes 312a and 312b may extend to the
bottom surface or a side surface of the package board 310. The
package board 310 may include an insulating resin and a ceramic
board. The first and second wiring electrodes 312a and 312b may
include a metal such as gold (Au), copper (Cu), silver (Ag), or
aluminum (Al). For example, the package board 310 may be a board
such as a printed circuit board (PCB), a metal core PCB (MCPCB), a
metal PCB (MPCB), or a flexible PCB (FPCB).
[0180] The semiconductor light emitting device 50 may be mounted on
the mounting surface such that a surface thereof on which first and
second electrodes E1 and E2 are disposed faces the mounting
surface, and the first electrode E1 and the second electrode E2 may
be connected to the first and second wiring electrodes 312a and
312b by solder bumps 315a and 315b, respectively.
[0181] A wavelength conversion film 344 may be disposed on a top
surface as a wavelength conversion unit, that is, a transparent
support substrate, of the semiconductor light emitting device 50
which is mounted on the package body 310. The wavelength conversion
film 344 includes a wavelength conversion material converting a
portion of light emitted from the semiconductor light emitting
device 50 into light having a different wavelength. The wavelength
conversion film 344 may be a ceramic film including a sintered body
of a ceramic phosphor and a resin layer in which the wavelength
conversion material is dispersed. When the semiconductor light
emitting device 50 emits blue light, the wavelength conversion film
344 may convert a portion of the blue light into yellow and/or red
and green light to provide the semiconductor light emitting device
package 340 emitting white light. Like the semiconductor light
emitting device 100 illustrated in FIG. 3, the wavelength
conversion material 174 of the transparent adhesive layer 175 may
include a first wavelength conversion material converting light
into light having a first wavelength, while the wavelength
conversion material of the wavelength conversion film 344 may
include a second wavelength conversion material converting light
into light having a second wavelength shorter than that of the
first wavelength. A wavelength conversion material that may be used
in the present example embodiment will be described hereinafter
(please refer to Table 2 below).
[0182] FIG. 9 is a cross-sectional view of a semiconductor light
emitting device package, according to an example embodiment of the
inventive concept.
[0183] Similar to the previous example embodiment, a semiconductor
light emitting device package 360 illustrated in FIG. 9 includes a
package board 350 having a mounting surface and a semiconductor
light emitting diode (LED) chip 50 flipchip-bonded to the mounting
surface of the package board 350.
[0184] The package board 350 may have a structure in which first
and second wiring electrodes 352a and 352b as lead frames are
united by an insulating resin part 351. The package board 350 may
further include a reflective structure 356 disposed on the mounting
surface and surrounding the semiconductor light emitting device 50.
The reflective structure 356 may have a cup shape in which an
internal surface thereof is sloped. A wavelength conversion part
364 employed in the present example embodiment may include a
wavelength conversion material 364a and a resin packing portion
364b containing the wavelength conversion material 364a. The
wavelength conversion part 364 may be formed to cover the
semiconductor light emitting device 50 within the reflective
structure 356.
[0185] Alternatively, as described above with reference to FIG. 3,
a wavelength conversion material may be contained in a different
component of the semiconductor light emitting device. Various
example embodiments thereof are illustrated in FIGS. 10 through
13.
[0186] A semiconductor light emitting device 50a illustrated in
FIG. 10 may be understood as being similar to the semiconductor
light emitting device 50 illustrated in FIG. 1, except that a
wavelength conversion material 74 is contained in a transparent
adhesive layer 75 and an optical filter layer 76 is added. The
components of the present example embodiment may be understood with
reference to the descriptions of the components the same as or
similar to those of the semiconductor light emitting device 50
illustrated in FIG. 1, unless otherwise mentioned.
[0187] In the present example embodiment, the transparent adhesive
layer 75 may act as a wavelength conversion element. The
transparent adhesive layer 75 may include a wavelength conversion
material 74 converting at least a portion of light having a first
wavelength generated by an active layer 35 into light having a
second wavelength. The transparent adhesive layer 75 may include at
least one adhesive material selected from the group consisting of
silicone, epoxy, polyacrylate, polyimide, polyamide, and
benzocyclobutene (BCB). The wavelength conversion material 74 may
be mixed in the adhesive material before being cured to thereby
provide the transparent adhesive layer 75 as a wavelength
conversion element.
[0188] The semiconductor light emitting device 50a may further
include the optical filter layer 76 disposed on a top surface (that
is, a surface from which light is emitted) of the transparent
support substrate 71. The optical filter layer 76 may be configured
to allow light within a required wavelength band to be selectively
transmitted therethrough, while selectively blocking light within
an undesired wavelength band. For example, the optical filter layer
76 may be an omnidirectional reflector (ODR) or a distributed Bragg
reflector (DBR). In this case, the optical filter layer 76 may be
formed by alternately forming two types of dielectric layers having
different refractive indices. Alternatively, the optical filter
layer 76 may include a material such as dye.
[0189] The optical filter layer 76 may serve to block unconverted
light (for example, blue light) having the first wavelength in
order to increase a rate of light (for example, green or red light)
having the second wavelength converted by the wavelength conversion
material 74 contained in the transparent adhesive layer 75, in
finally emitted light.
[0190] In the present example embodiment, the optical filter layer
76 is illustrated to be disposed on the top surface of the
transparent support substrate 71, but it may also be arranged in a
different position, as necessary. For example, the optical filter
layer 76 may be disposed between the transparent support substrate
71 and the transparent adhesive layer 75 (please refer to FIG.
13).
[0191] Also, a surface to which the transparent adhesive layer 75
is applied may be varied. As in the present example embodiment, a
first conductivity-type semiconductor layer 32' may not have a
concavo-convex portion on a junction surface thereof. In another
example, a surface on which a growth substrate or a buffer layer
remains, rather than being completely removed, may be used as a
junction surface.
[0192] A semiconductor light emitting device 50b illustrated in
FIG. 11 may be understood as being similar to the semiconductor
light emitting device 50a illustrated in FIG. 10, except that a
wavelength conversion material 74 is contained in a transparent
support substrate 71 and that a color filter layer 77 is added.
[0193] The transparent support substrate 71 may be a support
containing a wavelength conversion material 74 such as a phosphor
or a quantum dot. For example, the transparent support substrate 71
may be formed of a silicon resin mixed with a wavelength conversion
material or a transparent liquid resin such as an epoxy resin. In
another example, in a case where the transparent support substrate
71 is a glass substrate, a wavelength conversion material 74 such
as a phosphor may be mixed in a glass composition, and the mixture
may be sintered at a low temperature to manufacture a transparent
support substrate 71 containing the wavelength conversion material
74.
[0194] The color filter layer 77 may be disposed on the optical
filter layer 76. The color filter layer 77 may allow light having a
desired partial band of a converted wavelength to be selectively
transmitted therethrough. In an emission spectrum of finally
emitted light, the color filter layer 77 may form a narrow full
width at half maximum.
[0195] A semiconductor light emitting device 50c illustrated in
FIG. 12 may be understood as being similar to the semiconductor
light emitting device 50a illustrated in FIG. 10, except that a
light diffusion layer 78 may be added.
[0196] The semiconductor light emitting device 50c may include the
light diffusion layer 78 together with the color filter layer 77
described above with reference to FIG. 11. In this manner,
characteristics of finally emitted light may be changed by
including the additional optical element. The color filter layer 77
may be disposed on the optical filter layer 76. The color filter
layer 77 may allow light having a desired partial band of the
converted wavelength to be selectively transmitted therethrough. In
an emission spectrum of finally emitted light, the color filter
layer 77 may form a relatively narrow full width at half
maximum.
[0197] A semiconductor light emitting device 50d illustrated in
FIG. 13 may be understood as being similar to the semiconductor
light emitting device 50c illustrated in FIG. 12, except that an
optical filter layer 76, a color filter layer 77, and a light
diffusion layer 78 are disposed between a transparent support
substrate 71 and a transparent adhesive layer 75.
[0198] As in the present example embodiment, the optical filter
layer 76, the color filter layer 77, and the light diffusion layer
78 may be disposed between the transparent support substrate 71 and
the transparent adhesive layer 75. If necessary, the optical filter
layer 76, the color filter layer 77, and the light diffusion layer
78 may be provided on one surface of the transparent support
substrate 71 as a single stacked body before being adhered to a
light emitting structure 30.
[0199] In the aforementioned example embodiment, various materials
such as a phosphor and/or a quantum dot may be used. For example,
the aforementioned semiconductor light emitting device may include
at least one wavelength conversion element converting light into
light having a different wavelength so as to be provided as a white
light emitting device. For example, the semiconductor light
emitting device may include a yellow phosphor or a combination of
green and red phosphors.
[0200] FIG. 14 is a CIE 1931 color space diagram illustrating a
wavelength conversion material that may be used in a semiconductor
light emitting device or a semiconductor light emitting device
package, according to an example embodiment of the inventive
concept.
[0201] In a single light emitting device package, light having a
required color may be determined depending on a wavelength of light
from a light emitting diode (LED) chip, a light emitting device,
and a phosphor type and a combination ratio of phosphors. In the
case of the white light emitting device package, a color
temperature and a color rendering index may be controlled
thereby.
[0202] For example, semiconductor light emitting devices may be
combined with phosphors selected from yellow, green, red, and blue
phosphors to be appropriate therefor, thereby implementing white
light, and may emit white light having various color temperatures
according to a selected phosphor combination ratio.
[0203] In this case, in a lighting apparatus, a color rendering
index (CRI) may be adjusted from a level of a sodium-vapor lamp to
a level of sunlight, and various types of white light having a
color temperature of around 1500K to around 20000K may be
generated. In addition, a lighting color may be adjusted to be
appropriate for an ambient atmosphere or for viewer mood by
generating violet, blue, green, red, orange visible light or
infrared light as needed. Further, the lighting apparatus may also
emit light within a special wavelength band, capable of promoting
plant growth.
[0204] White light obtained by combining yellow, green, red, blue
phosphors and/or green and red light emitting devices with a
semiconductor light emitting device may have two or more peak
wavelengths, and coordinates (x, y) of the CIE 1931 color space
diagram illustrated in FIG. 14 may be located on line segments
(0.4476, 0.4074), (0.3484, 0.3516), (0.3101, 0.3162), (0.3128,
0.3292), and (0.3333, 0.3333) connected to one another.
Alternatively, the coordinates (x, y) may be located in a region
surrounded by the line segments and a blackbody radiation spectrum.
A color temperature of white light may be within a range of 1500K
to 20000K. In FIG. 14, white light in the vicinity of a point E
(0.3333, 0.3333) below the blackbody radiation spectrum may be in a
state in which light of a yellow-based component becomes relatively
weak. This white light may be used as an illumination light source
in a region in which a relatively bright or refreshing mood may be
provided to the naked eye. Thus, a lighting apparatus product using
white light in the vicinity of the point E (0.3333, 0.3333) below
the blackbody radiation spectrum (a Planckian locus) may be
effective for use in retail spaces in which consumer goods are for
sale.
[0205] Phosphors may be represented by the following empirical
formulae and have colors as below. [0206] Oxide-based Phosphor:
Yellow and green Y.sub.3Al.sub.5O.sub.12:Ce,
Tb.sub.3Al.sub.5O.sub.12: Ce, Lu.sub.3Al.sub.5O.sub.12: Ce [0207]
Silicate-based Phosphor: Yellow and green
(Ba,Sr).sub.2SiO.sub.4:Eu, Yellow and yellowish-orange
(Ba,Sr).sub.3SiO.sub.5:Ce [0208] Nitride-based Phosphor: Green
.beta.-SiAlON:Eu, Yellow La.sub.3Si.sub.6N.sub.11:Ce, Yellow
.alpha.-SiAlON:Eu, Red CaAlSiN.sub.3:Eu,
Sr.sub.2Si.sub.5N.sub.8:Eu, SrSiAl.sub.4N.sub.7:Eu,
SrLiAl.sub.3N.sub.4:Eu,
Ln.sub.4-x(Eu.sub.zM.sub.1-z).sub.xSi.sub.12-yAl.sub.yO.sub.3+x+yN.sub.18-
-x-y (0.5.ltoreq.x.ltoreq.3, 0<z<0.3,
0<y.ltoreq.4)--Formula (1) (Here, Ln may be at least one element
selected from a group consisting of group IIIa elements and
rare-earth elements, and M may be at least one element selected
from a group consisting of calcium (Ca), barium (Ba), strontium
(Sr), and magnesium (Mg). [0209] Fluoride-based Phosphor: KSF-based
red K.sub.2SiF.sub.6:Mn.sup.4+, K.sub.2TiF.sub.6:Mn.sup.4+,
NaYF.sub.4:Mn.sup.4+, NaGdF.sub.4:Mn.sup.4+,
K.sub.3SiF.sub.7:Mn.sup.4+
[0210] A composition of a phosphor should basically conform to
stoichiometry, and respective elements may be substituted with
other elements in respective groups of the periodic table of
elements. For example, Sr may be substituted with Ba, Ca, Mg, or
the like, of an alkaline earth group II, and Y may be substituted
with lanthanum-based terbium (Tb), lutetium (Lu), scandium (Sc),
gadolinium (Gd), or the like. In addition, Eu or the like, an
activator, may be substituted with cerium (Ce), Tb, praseodymium
(Pr), erbium (Er), ytterbium (Yb), or the like, according to a
required energy level. In this case, an activator may be used
alone, or a sub-activator or the like, for modification of
characteristics thereof, may additionally be used.
[0211] The following table 2 illustrates phosphor types of white
light emitting devices using a UV LED chip (200 to 430 nm).
TABLE-US-00002 TABLE 2 Purpose Phosphor LED TV
.beta.-SiAlON:Eu.sup.2+, (Ca,Sr)AlSiN.sub.3:Eu.sup.2+, BLU
La.sub.3Si.sub.6N.sub.11:Ce.sup.3+, K.sub.2SiF.sub.6:Mn.sup.4+,
SrLiAl.sub.3N.sub.4:Eu, Ln.sub.4-x
(Eu.sub.zM.sub.1-z).sub.xSi.sub.12-yAl.sub.yO.sub.3+x+yN.sub.18-x-y(0.5
.ltoreq. x .ltoreq. 3, 0 < z < 0.3, 0 < y .ltoreq. 4),
K.sub.2TiF.sub.6:Mn.sup.4+, NaYF.sub.4:Mn.sup.4+,
NaGdF.sub.4:Mn.sup.4+ Lighting Lu.sub.3Al.sub.5O.sub.12:Ce.sup.3+,
Ca-.alpha.-SiAlON:Eu.sup.2+, La.sub.3Si.sub.6N.sub.11:Ce.sup.3+,
(Ca,Sr)AlSiN.sub.3:Eu.sup.2+, Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+,
K.sub.2SiF.sub.6:Mn.sup.4+, SrLiAl.sub.3N.sub.4:Eu,
Ln.sub.4-x(Eu.sub.zM.sub.1-z).sub.xSi.sub.12-yAl.sub.yO.sub.3+x+yN.sub.18-
-x-y (0.5 .ltoreq. x .ltoreq. 3, 0 < z < 0.3, 0 < y
.ltoreq. 4), K.sub.2TiF.sub.6:Mn.sup.4+, NaYF.sub.4:Mn.sup.4+,
NaGdF.sub.4:Mn.sup.4+ Side Lu.sub.3Al.sub.5O.sub.12:Ce.sup.3+,
Ca-.alpha.-SiAlON:Eu.sup.2+, La.sub.3Si.sub.6N.sub.11:Ce.sup.3+,
Viewing (Ca,Sr)AlSiN.sub.3:Eu.sup.2+,
Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+, (Sr,Ba, (Mobile
Ca,Mg).sub.2SiO.sub.4:Eu.sup.2+, K.sub.2SiF.sub.6:Mn.sup.4+,
SrLiAl.sub.3N.sub.4:Eu, Devices,
Ln.sub.4-x(Eu.sub.zM.sub.1-z).sub.xSi.sub.12-yAl.sub.yO.sub.3+x+y-
N.sub.18-x-y(0.5 .ltoreq. x .ltoreq. 3, Laptop PCs) 0 < z <
0.3, 0 < y .ltoreq. 4), K.sub.2TiF.sub.6:Mn.sup.4+,
NaYF.sub.4:Mn.sup.4+, NaGdF.sub.4:Mn.sup.4+ Electrical
Lu.sub.3Al.sub.5O.sub.12:Ce.sup.3+, Ca-.alpha.-SiAlON:Eu.sup.2+,
La.sub.3Si.sub.6N.sub.11:Ce.sup.3+, Components
(Ca,Sr)AlSiN.sub.3:Eu.sup.2+, Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+,
K.sub.2SiF.sub.6:Mn.sup.4+, (Headlamps, SrLiAl.sub.3N.sub.4:Eu,
Ln.sub.4-x(Eu.sub.zM.sub.1-z).sub.xSi.sub.12-yAl.sub.yO.sub.3+x+yN.sub.18-
-x-y etc.) (0.5 .ltoreq. x .ltoreq. 3, 0 < z < 0.3, 0 < y
.ltoreq. 4), K.sub.2TiF.sub.6:Mn.sup.4+, NaYF.sub.4:Mn.sup.4+,
NaGdF.sub.4: Mn.sup.4+
[0212] In addition, as the wavelength conversion material, a
quantum dot (QD) may be used by substituting a phosphor therewith
or being mixed with a phosphor. The quantum dot may be implemented
to exhibit various colors according to a size thereof, and in
addition, in a case where the quantum dot is used as a phosphor
substitute, the quantum dot may be used as a red or green phosphor.
In the case of using a quantum dot, a narrow full width at half
maximum of, for example, about 35 nm may be implemented.
[0213] Although the wavelength conversion material may be
implemented in a manner in which it is contained in an
encapsulation portion, the wavelength conversion material may also
be previously formed in the form of a film to be used by being
adhered to a surface of an optical structure such as a
semiconductor light emitting device or a light guide plate. In this
case, the wavelength conversion material may be easily applied to a
required region in a uniform thickness structure, and may be
usefully used in a backlight unit, a display device, or various
types of light source devices such as a lighting apparatus (see
FIGS. 36 to 44).
[0214] FIGS. 15A and 15B are side cross-sectional views of a
semiconductor light emitting device 500, according to an example
embodiment of the inventive concept, and FIG. 15C is a bottom view
of the semiconductor light emitting device 500 illustrated in FIG.
15A, according to an example embodiment.
[0215] Specifically, FIG. 15B is a cross-sectional view of the
semiconductor light emitting device 500 illustrated in FIG. 15A,
but an electrode structure is not illustrated. The semiconductor
light emitting device 500 according to the example embodiment of
the inventive concept may be a chip scale package (CSP) or a wafer
level package (WLP). As described above, the terms "upper portion",
"top surface", "lower portion", "bottom surface", and "side
surface" are based on the drawings and may be changed according to
an actual arrangement direction. In the drawings of the present
specification, only necessary elements are illustrated.
[0216] The semiconductor light emitting device 500 may have a
light-emitting structure 515p including a first conductivity type
semiconductor layer 509p, an active layer 511p, and a second
conductivity type semiconductor layer 513p. The first conductivity
type semiconductor layer 509p may be an n-type semiconductor layer.
The second conductivity type semiconductor layer 513p may be a
p-type semiconductor layer.
[0217] The first conductivity type semiconductor layer 509p and the
second conductivity type semiconductor layer 513p may include a
nitride semiconductor, for example, GaN or InGaN. The first
conductivity type semiconductor layer 509p and the second
conductivity type semiconductor layer 513p may include a nitride
semiconductor, for example, Al.sub.xIn.sub.yGa.sub.1-x-yN
(0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.x+y.ltoreq.1).
Each of the first conductivity type semiconductor layer 509p and
the second conductivity type semiconductor layer 513p may be a
single layer or a plurality of layers having different doping
concentrations, different compositions, or the like. Alternatively,
the first conductivity type semiconductor layer 509p and the second
conductivity type semiconductor layer 513p may include an
AlInGaP-based semiconductor or an AlInGaAs-based semiconductor.
[0218] The active layer 511p between the first conductivity type
semiconductor layer 509p and the second conductivity type
semiconductor layer 513p may emit light having predetermined energy
level through a recombination of electrons and holes. The active
layer 511p may have a multi-quantum well (MQW) structure in which a
quantum well layer and a quantum barrier layer are alternately
stacked. In the case of a nitride semiconductor, a GaN/InGaN
structure may be used. The active layer 511p may have a single
quantum well (SQW) structure using a nitride semiconductor.
[0219] The light-emitting structure 515p may include a first
through hole 527. The first through hole 527 may be referred to as
a first through-via hole or a first via hole. As illustrated in
FIG. 15B, the first through hole 527 may pass through the first
conductivity type semiconductor layer 509p, the active layer 511p,
and the second conductivity type semiconductor layer 513p.
[0220] An etch stop layer 517p may be on the second conductivity
type semiconductor layer 513p of the light-emitting structure 515p.
The etch stop layer 517p may include a second through hole 529
passing through the first through hole 527. The second through hole
529 may be referred to as a second through-via hole or a second via
hole. As described below, the etch stop layer 517p may stop etching
when the first through hole 527 is formed. The second through hole
529 may be inside the etch stop layer 517p. The etch stop layer
517p may include a silicon oxide (SiO.sub.2) layer.
[0221] A current spreading layer 519 may be on the second
conductivity type semiconductor layer 513p, the second through hole
529, and the etch stop layer 517p, which constitute the
light-emitting structure 515p. The current spreading layer 519 may
be an indium tin oxide (ITO) layer. The current spreading layer 519
may be on a top surface of the second conductivity type
semiconductor layer 513p, a top surface of the second through hole
529, and a side surface of the etch stop layer 517p, which
constitute the light-emitting structure 515p. The current spreading
layer 519 may be provided for applying a voltage to the second
conductivity type semiconductor layer 513p.
[0222] The semiconductor light emitting device 500 may further
include a reflective layer 533p on internal walls of the first
through hole 527 and the second through hole 529 and a bottom
surface of the first conductivity type semiconductor layer 509p.
The reflective layer 533p may reflect light generated by the
light-emitting structure 515p. The reflective layer 533p may be
formed when necessary. The reflective layer 533p may include silver
(Ag) or copper (Cu). The reflective layer 533p may be a distributed
Bragg reflector (DBR). The distributed Bragg reflector may be a
multilayer reflective layer in which a first insulating film having
a first refractive index and a second insulating film having a
second refractive index are alternately stacked.
[0223] The semiconductor light emitting device 500 may further
include electrode structures 531_1, 537_1, 539_1, 531_2, 537_2, and
539_2 on the bottom surface of the first conductivity type
semiconductor layer 509p. The electrode structures 531_1, 537_1,
539_1, 531_2, 537_2, and 539_2 may include a conductive material
layer, for example, a metal layer. The electrode structures 531_1,
537_1, 539_1, 531_2, 537_2, and 539_2 may include first electrode
structures 531_1, 537_1, and 539_1 and second electrode structures
531_2, 537_2, and 539_2.
[0224] The first electrode structures 531_1, 537_1, and 539_1 may
include a first contact layer 531_1 on the bottom surface of the
first conductivity type semiconductor layer 509p, and first
electrode layers 537_1 and 539_1 electrically connected to the
first contact layer 531_1. The first electrode layers 537_1 and
539_1 may be referred to as first via electrode layers. The first
electrode structures 531_1, 537_1, and 539_1 may be electrically
connected to the first conductivity type semiconductor layer 509p
on the bottom surface of the first conductivity type semiconductor
layer 509p. The first contact layer 531_1 may be an n-type contact
layer.
[0225] The second electrode structures 531_2, 537_2, and 539_2 may
include a second contact layer 531_2 on a bottom surface of the
current spreading layer 519 inside the second through hole 529, and
second electrode layers 537_2 and 539_2 electrically connected to
the second contact layer 531_2. The second electrode layers 537_2
and 539_2 may be referred to as second via electrode layers. The
second electrode structures 531_2, 537_2, and 539_2 may be
electrically connected to the current spreading layer 519 through
the first through hole 527 and the second through hole 529 on the
bottom surface of the first conductivity type semiconductor layer
509p. The second electrode structures 531_2, 537_2, and 539_2 may
be electrically connected to the second conductivity type
semiconductor layer 513p. The second contact layer 531_2 may be a
p-type contact layer.
[0226] Each of the first contact layer 531_1 and the second contact
layer 531_2 may include one selected from the group consisting of
conductive materials, for example, Ag, Al, Ni, Cr, Cu, Au, Pd, Pt,
Sn, W, Rh, Ir, Ru, Mg, Zn, Ti, and alloys thereof. The first
electrode layers 537_1 and 539_1 and the second electrode layers
537_2 and 539_2 may be a multilayer structure of first and second
barrier metal layers 537_1 and 537_2 and first and second pad bump
metal layers 539_1 and 539_2.
[0227] In the present example embodiment, the first electrode
layers 537_1 and 539_1 and the second electrode layers 537_2 and
539_2 are provided in a dual layer structure, but may be provided
as a single layer structure. The first electrode layers 537_1 and
539_1 and the second electrode layers 537_2 and 539_2 may include
the same material as the first contact layer 531_1 and the second
contact layer 531_2.
[0228] The first electrode layers 537_1 and 539_1 may be
electrically connected to the first contact layer 531_1 on the
bottom surface of the first conductivity type semiconductor layer
509p. The barrier metal layer 537_1 constituting the first
electrode layers 537_1 and 539_1 may be formed on the bottom
surface of the first conductivity type semiconductor layer 509p and
may be electrically connected to the first contact layer 531_1.
Reference numeral 530_1 of FIG. 15C may indicate a portion that
contacts the first conductivity type semiconductor layer 509p.
[0229] The second electrode layers 537_2 and 539_2 may be on the
bottom surface of the first conductivity type semiconductor layer
509p and may be electrically connected to the second contact layer
531_2 through the first through hole 527 and the second through
hole 529. The second electrode layers 537_2 and 539_2 may be
electrically connected to the second conductivity type
semiconductor layer 513p through the second contact layer 531_2.
Reference numeral 530_2 of FIG. 15C may indicate a portion that
contacts the second conductivity type semiconductor layer 513p.
[0230] In a case where the reflective layer 533p is formed in the
semiconductor light emitting device 500, the reflective layer 533p
may be formed on bottom surfaces and sidewalls of the first contact
layer 531_1 and the second contact layer 531_2. in a case where the
reflective layer 533p is formed in the semiconductor light emitting
device 500, the first electrode layers 537_1 and 539_1 and the
second electrode layers 537_2 and 539_2 may be formed on the bottom
surface of the reflective layer 533p.
[0231] The semiconductor light emitting device 500 may further
include a graded index layer 521 on the current spreading layer
519. The graded index layer 521 may be a material layer that
improves the light extraction efficiency of the semiconductor light
emitting device 500. The graded index layer 521 may be a material
layer that reduces a refractive index when light travels from the
active layer (e.g., a GaN layer) having a refractive index of about
2.47 to an air layer having a refractive index of 1. As such, in
the semiconductor light emitting device 500, in a case where the
refractive index is reduced by using the graded index layer 521,
the light extraction efficiency of the semiconductor light emitting
device 500 may be improved.
[0232] The graded index layer 521 may be a multilayer structure of
a titanium oxide (TiO.sub.2) layer and a silicon oxide (SiO.sub.2)
layer. When the graded index layer 521 is a multilayer structure of
a titanium oxide (TiO.sub.2) layer and a silicon oxide (SiO.sub.2)
layer, the graded index layer 521 may adjust a level of refractive
index to about 1.83 to about 2.26.
[0233] The graded index layer 521 may be an obliquely-deposited ITO
layer on the top surface of the current spreading layer 519. That
is, as the graded index layer 521, the obliquely-deposited ITO
layer may be formed by depositing an ITO source obliquely at a
predetermined angle with respect to a direction perpendicular to
the top surface of the current spreading layer 519. When the graded
index layer 521 is the obliquely-deposited ITO layer, the graded
index layer 521 may adjust a refractive index to about 1.5 to about
2.1.
[0234] A transparent adhesive layer 523 and a transparent support
substrate 525 may be on the graded index layer 521. The transparent
adhesive layer 523 may adhere the transparent support substrate 525
to the graded index layer 521. When the graded index layer 521 is
not formed, the transparent adhesive layer 523 may adhere the
current spreading layer 519 to the transparent support substrate
525.
[0235] The transparent adhesive layer 523 may include a material
selected from polyacrylate, polyimide, polyamide, and
benzocyclobutene (BCB). The transparent adhesive layer 523 may be a
refractive index matching layer for matching to a refractive index
between the transparent support substrate 525 (or the graded index
layer 521) and the light emitting structure 515p.
[0236] The transparent support substrate 525 may include any
transparent material. The transparent support substrate 525 may
include glass. Besides the glass, the transparent support substrate
525 may include a material having excellent light transparency,
such as silicone, epoxy, or plastic. The transparent adhesive layer
523 may include a material that is optically transparent, is stable
at a high temperature, and has high chemical/mechanical stability.
The transparent adhesive layer 523 may include a benzocyclobutene
(BCB)-based polymer, a polydimethylsiloxane (PDMS), a UV curing
agent, and a thermal hardener.
[0237] The transparent support substrate 525 may be a support
structure containing a wavelength conversion material such as a
phosphor or a quantum dot. For example, the transparent support
substrate 525 may be formed of a silicon resin mixed with a
wavelength conversion material or a transparent liquid resin such
as an epoxy resin.
[0238] In another example, when the transparent support substrate
525 is a glass substrate, a support containing a wavelength
conversion material may be manufactured by mixing a wavelength
conversion material such as a phosphor with a glass composition and
sintering the mixture at a relatively low temperature.
[0239] In the case of using the transparent support substrate 525,
the graded index layer 521 may be simply adhered to the transparent
support substrate 525 using the transparent adhesive layer 523,
without using a temporal bonding process or a eutectic bonding
process.
[0240] In the semiconductor light emitting device 500 according to
the present example embodiment, since the first electrode layers
537_1 and 539_1 and the second electrode layers 537_2 and 539_2
provided below the light-emitting structure 515p function as
electrode pads, the first electrode layers 537_1 and 539_1 and the
second electrode layers 537_2 and 539_2 may be directly mounted on
an external device or an external substrate in a flip-chip
structure.
[0241] The semiconductor light emitting device 500 according to the
present example embodiment may improve the light extraction
efficiency by forming the graded index layer 521 on the
light-emitting structure 515p or by forming the reflective layer
533p on the surface of the first conductivity type semiconductor
layer 509p of the light-emitting structure 515p and inside the
through holes 527 and 529 formed in the light-emitting structure
515p.
[0242] FIGS. 16A to 28A and FIGS. 16B to 28B are diagrams
illustrating a method of manufacturing a semiconductor light
emitting device, according to an example embodiment of the
inventive concept. FIGS. 16B to 21B are plan views of FIGS. 16A to
21A, respectively, and FIGS. 22B to 28B are bottom views of FIGS.
22A to 28A, respectively.
[0243] Referring to FIGS. 16A and 16B, a light-emitting structure
515 may be formed on a growth substrate 501. The growth substrate
501 may be a semiconductor wafer. The growth substrate 501 may be a
silicon-based substrate. The silicon-based substrate may be a
silicon (Si) substrate or a silicon carbide (SiC) substrate. When
the silicon-based substrate is used as the growth substrate 501, it
may be more suitable for an increase in a diameter of a wafer, and
package productivity may be improved due to relatively low
costs.
[0244] The growth substrate 501 may include an insulating material,
a conductive material, or a semiconductor substrate, such as
sapphire, SiC, MgAl.sub.2O.sub.4, MgO, LiAlO.sub.2, and
LiGaO.sub.2. Sapphire widely used in a substrate for growth of
nitride semiconductor is a crystal having electrical insulating
properties and hexa-rhombo R3c symmetry. Sapphire may have a
lattice constant of about 13.001 .ANG. and about 4.758 .ANG. in a
c-axis direction and an a-axis direction and have a C(0001) plane,
an A(1120) plane, and an R(1102) plane. In this case, since the C
plane relatively facilitates the growth of a nitride thin film and
is stable at a high temperature, it may be used as a substrate for
the growth of a nitride material.
[0245] Buffer layers 503, 505, and 507 may be formed on the growth
substrate 501. When the silicon-based substrate is used as the
growth substrate 501, the buffer layers 503, 505, and 507 may be
further required. The buffer layers 503, 505, and 507 may be layers
for growing a nitride laminate having excellent quality, such as
less cracks or lower potential.
[0246] The buffer layers 503, 505, and 507 may include a nucleus
growth layer 503, a first buffer layer 505, and a second buffer
layer 507. The nucleus growth layer 503 may include AlN. The first
buffer layer 505 and the second buffer layer 507 may have a defect
reducing function and may include Al.sub.xIn.sub.yGa.sub.1-x-yN
(0.ltoreq.x<1, 0.ltoreq.y<1, 0.ltoreq.x+y<1).
[0247] In detail, the buffer layers 503, 505 and 507 may be
implemented by any one of structures described with reference to
FIGS. 7A to 7D.
[0248] A light-emitting structure 515 may be formed by sequentially
growing a first conductivity type semiconductor layer 509, an
active layer 511, and a second conductivity type semiconductor
layer 513 on the substrate 501 or the buffer layers 503, 505, and
507. The light-emitting structure 515 may be grown by using a metal
organic chemical vapor deposition (MOCVD) process, a hydride vapor
phase epitaxy (HVPE) process, a molecular beam epitaxy (MBE)
process, or the like.
[0249] Referring to FIGS. 17A and 17B, an etch stop layer 517 may
be formed on the second conductivity type semiconductor layer 513
of the light-emitting structure 515. The etch stop layer 517 may
stop etching when a first through hole is formed in a subsequent
process. The etch stop layer 517 may include a silicon oxide
(SiO.sub.2) layer.
[0250] As illustrated in FIG. 17B, the etch stop layer 517 may
include a plurality of patterns spaced apart from one another when
seen in a plan view. In addition, the etch stop layer 517 may
include a circular pattern 517_1 and a bar-shaped pattern 517_2.
The etch stop layer 517 may be formed by connecting the circular
pattern 517_1 and the bar-shaped pattern 517_2.
[0251] Referring to FIGS. 18A and 18B, a current spreading layer
519 may be formed on the top surfaces of the second conductivity
type semiconductor layer 513 and the etch stop layer 517. The
current spreading layer 519 may be an ITO layer. The current
spreading layer 519 may be formed on the top surface of the second
conductivity type semiconductor layer 513 and the top surface and
the side surface of the etch stop layer 517.
[0252] The current spreading layer 519 may be formed for applying a
voltage to the second conductivity type semiconductor layer 513. As
illustrated in FIG. 18B, the current spreading layer 519 may be
formed on an entire top surface of the etch stop layer 517. That
is, the current spreading layer 519 may be formed on the entire top
surface of the etch stop layer 517 including the circular pattern
517_1 and the bar-shaped pattern 517_2 described above with
reference to FIG. 17B.
[0253] Referring to FIGS. 19A and 19B, a graded index layer 521 may
be formed on the current spreading layer 519. As described above,
the graded index layer 521 may be a material layer that improves
light extraction efficiency. The graded index layer 521 may be a
multilayer structure of a titanium oxide (TiO.sub.2) layer and a
silicon oxide (SiO.sub.2) layer. When the graded index layer 521 is
a multilayer structure of a titanium oxide (TiO.sub.2) layer and a
silicon oxide (SiO.sub.2) layer, the graded index layer 521 may
adjust a refractive index to about 1.83 to about 2.26.
[0254] The graded index layer 521 may be an obliquely-deposited ITO
layer on a top surface of the current spreading layer 519. That is,
as the graded index layer 521, an obliquely-deposited ITO layer may
be formed by depositing an ITO source obliquely at a predetermined
angle with respect to a direction perpendicular to the top surface
of the current spreading layer 519. When the graded index layer 521
is an obliquely-deposited ITO layer, the graded index layer 521 may
adjust a refractive index to about 1.5 to about 2.1. The graded
index layer 521 may be formed over the entire top surface of the
etch stop layer 517 including the circular pattern 517_1 and the
bar-shaped pattern 517_2 described above with reference to FIG.
17B.
[0255] Referring to FIGS. 20A and 20B, a transparent adhesive layer
523 may be formed on the graded index layer 521. The transparent
adhesive layer 523 may serve to adhere a transparent support
substrate to be formed in a subsequent process. As described above,
the transparent adhesive layer 523 may include a material that is
optically transparent, is stable at a high temperature, and has
high chemical/mechanical stability. The transparent adhesive layer
523 may include a benzocyclobutene (BCB)-based polymer, a
polydimethylsiloxane (PDMS), a UV curing agent, and a thermal
hardener.
[0256] Referring to FIGS. 21A and 21B, a transparent support
substrate 525 may be adhered to the transparent adhesive layer 523.
The graded index layer 521 and the transparent support substrate
525 may be adhered to each other using the transparent adhesive
layer 523. The transparent support substrate 525 may include any
transparent materials. In the case of using the transparent support
substrate 525, the graded index layer 521 may be simply adhered to
the transparent support substrate 525 by using the transparent
adhesive layer 523, without using a temporal bonding process or a
eutectic bonding process.
[0257] Referring to FIGS. 22A and 22B, the growth substrate 501 may
be removed by using the transparent support substrate 525. The
removal of the growth substrate 501 may be performed by using a wet
etching process, a dry etching process, or a laser lift-off (LLO)
process. In addition, according to some example embodiments, a
mechanical polishing process may be used. Since the transparent
support substrate 525 is adhered to the second conductivity type
semiconductor layer 513 of the light-emitting structure 515, the
growth substrate 501 may be easily removed from the first
conductivity type semiconductor layer 509 of the light-emitting
structure 515.
[0258] FIG. 22B is a bottom view of FIG. 22A that illustrates the
etch stop layer 517. The etch stop layer 517 may include the
circular pattern 517_1 and the bar-shaped pattern 517_2 described
above with reference to FIG. 17B.
[0259] Referring to FIGS. 23A and 23B, a first through hole 527
passing through the first conductivity type semiconductor layer
509, the active layer 511, and the second conductivity type
semiconductor layer 513 may be formed by using the etch stop layer
517 as an etch stop film. The first through hole 527 may be formed
to expose the bottom surface of the etch stop layer 517.
[0260] The first through hole 527 may be formed by forming a mask
layer (not illustrated) on the first conductivity type
semiconductor layer 509 and etching the first conductivity type
semiconductor layer 509, the active layer 511, and the second
conductivity type semiconductor layer 513 by using a wet etching
process or a dry etching process.
[0261] FIG. 23B is a bottom view of FIG. 23A that illustrates the
etch stop layer 517. The etch stop layer 517 may include the
circular pattern 517_1 and the bar-shaped pattern 517_2 described
above with reference to FIG. 17B. In addition, the first through
hole 527 may include a circular pattern 527_1 and a bar-shaped
pattern 527_2 as in the etch stop layer 517.
[0262] Referring to FIGS. 24A and 24B, a second through hole 529
communicating with the first through hole 527 may be formed by
etching the etch stop layer 517 exposed by the first through hole
527. The second through hole 529 may be formed to expose the bottom
surface of the current spreading layer 519. The second through hole
529 may be formed inside the etch stop layer 517. The second
through hole 529 may be formed by etching the etch stop layer 517
exposed by the first through hole 527, by using a wet etching
process or a dry etching process.
[0263] In the drawings subsequent to FIGS. 24A and 24B, the
light-emitting structure 515 with the first through hole 527 is
denoted by 515p. In addition, the first conductivity type
semiconductor layer 509, the active layer 511, and the second
conductivity type semiconductor layer 513 are denoted by 505p,
511p, and 513p, respectively.
[0264] Further, in the drawings subsequent to FIGS. 24A and 24B,
the etch stop layer 517 with the second through hole 529 is denoted
by 517p. FIG. 24B is a bottom view of FIG. 24A that illustrates the
current spreading layer 519. In addition, the second through hole
529 may include a circular pattern 529_1 and a bar-shaped pattern
529_2.
[0265] Referring to FIGS. 25A and 25B, a first contact layer 531_1
and a second contact layer 531_2 may respectively be formed on the
bottom surface of the first conductivity type semiconductor layer
509p and the bottom surface of the second through hole 529. The
first contact layer 531_1 may have a first electrode structure and
may be electrically connected to the first conductivity type
semiconductor layer 509p. The first contact layer 531_1 may be an
n-type contact layer.
[0266] The second contact layer 531_2 may have a second electrode
structure and may be electrically connected to the second
conductivity type semiconductor layer 513p through the current
spreading layer 519. The second contact layer 531_2 may be a p-type
contact layer.
[0267] FIG. 25B is a bottom view of FIG. 25A. The first contact
layer 531_1 and the second contact layer 531_2 may be formed inside
the second through hole 529 including the circular pattern 529_1
and the bar-shaped pattern 529_2. Each of the first contact layer
531_1 and the second contact layer 531_2 may include a circular
pattern and a bar-shaped pattern.
[0268] Referring to FIGS. 26A and 26B, a reflective layer 533 may
be formed on the internal walls of the first through hole 527 and
the second through hole 529, bottom surfaces of the first contact
layer 531_1 and the second contact layer 531_2, and a bottom
surface of the first conductivity type semiconductor layer 509p.
The reflective layer 533p may be formed on an entire bottom surface
of the light-emitting structure 515p.
[0269] The reflective layer 533 may reflect light generated by the
light-emitting structure 515p. The reflective layer 533p may be a
silver layer or a copper layer. The reflective layer 533p may be a
distributed Bragg reflector (DBR).
[0270] FIG. 26B is a bottom view of FIG. 26A as described above. As
illustrated in FIG. 26B, the reflective layer 533 may be formed on
the bottom surfaces of the first contact layer 531_1 and the second
contact layer 531_2 formed inside the second through hole 529
including the circular pattern 529_1 and the bar-shaped pattern
529_2, and the bottom surface of the first conductivity type
semiconductor layer 509p.
[0271] Referring to FIGS. 27A and 27B, the reflective layer 533 may
be etched to expose the bottom surfaces of the first contact layer
531_1 and the second contact layer 531_2. A mask layer (not
illustrated) may be formed on the reflective layer 533. The bottom
surfaces of the first contact layer 531_1 and the second contact
layer 531_2 may be exposed by etching the reflective layer 533
through a wet etching process or a dry etching process by using the
mask layer as an etching mask. In the drawings subsequent to FIGS.
27A and 27B, the etched reflective layer 533 is denoted by
533p.
[0272] FIG. 27B is a bottom view of FIG. 27A as described above. As
illustrated in FIG. 27B, the bottom surfaces of the first contact
layer 531_1 and the second contact layer 531_2 formed inside the
second through hole 529 including the circular pattern 529_1 and
the bar-shaped pattern 529_2 may be exposed, and the reflective
layer 533p may be formed on the bottom surface of the first
conductivity type semiconductor layer 509p.
[0273] Referring to FIGS. 28A and 28B, barrier metal layers 537_1
and 537_2 electrically connected to the first contact layer 531_1
and the second contact layer 531_2 may be formed on the bottom
surface of the reflective layer 533p. The barrier metal layer 537_1
may constitute a first electrode layer, and the barrier metal layer
537_2 may constitute a second electrode layer.
[0274] The barrier metal layer 537_1 may be formed on the bottom
surface of the first conductivity type semiconductor layer 509p and
may be electrically connected to the first contact layer 531_1. The
barrier metal layer 537_2 may be formed on the bottom surface of
the reflective layer 533p and may be electrically connected to the
second contact layer 531_2 through the first through hole 527 and
the second through hole 529.
[0275] FIG. 28B is a bottom view of FIG. 28A as described above. As
illustrated in FIG. 28B, the barrier metal layers 537_1 and 537_2
electrically connected to the first conductivity type semiconductor
layer 509p and the second conductivity type semiconductor layer
513p may be formed on the reflective layer 533p. In FIG. 28B,
reference numeral 530_1 may indicate a portion that contacts the
first conductivity type semiconductor layer 509p. Reference numeral
530_2 may indicate a portion that contacts the second conductivity
type semiconductor layer 513p.
[0276] FIG. 29 is a cross-sectional view of a semiconductor light
emitting device 500a, according to another example embodiment of
the inventive concept.
[0277] Referring to FIG. 29, the semiconductor light emitting
device 500a of FIG. 29 may be substantially identical to the
semiconductor light emitting device 500 of FIG. 15A, except that a
concave/convex structure P is formed on a top surface of a
transparent support substrate 525 and a wavelength conversion
material is contained in the transparent adhesive layer. In some
example embodiments, although not illustrated in FIG. 29, a
concave/convex structure may also be formed on a top surface of a
second conductivity type semiconductor layer 513p.
[0278] Due to the concave/convex structure P, when light emitted
from an active layer 511p is incident on an external air layer, the
light may be transmitted or multi-reflected and be guided upward.
Therefore, the light extraction efficiency of the semiconductor
light emitting device 500a may be increased. The concave/convex
structure P may be formed by etching the upper portion of the
transparent support substrate 525.
[0279] A transparent adhesive layer 523' may contain a wavelength
conversion material 524 converting at least a portion of light
having a first wavelength generated by the active layer 511p into
light having a second wavelength. The transparent adhesive layer
523' may include at least one adhesive material selected from a
group consisting of silicone, an epoxy, polyacrylate, polyimide,
polyamide, and benzocyclobutene. The wavelength conversion material
524 may be mixed with the adhesive material before being cured to
thereby provide the transparent adhesive layer 523' as a wavelength
conversion element.
[0280] FIG. 30 is a cross-sectional view of a semiconductor light
emitting device 500b, according to another example embodiment of
the inventive concept.
[0281] Referring to FIG. 30, the semiconductor light emitting
device 500b of FIG. 30 may be substantially identical to the
semiconductor light emitting device 500 of FIG. 15A, except that a
wavelength conversion layer 524' may be formed between a
transparent adhesive layer 523 and a transparent support substrate
525.
[0282] In the semiconductor light emitting device 500b of FIG. 30,
the wavelength conversion layer 524' may be formed on the bottom
surface of the transparent support substrate 525. The wavelength
conversion layer 524' may include a phosphor that is excited by
light emitted from a light-emitting structure 515p and emits light
having different wavelengths. When light is emitted through the
phosphor, desired output light such as white light may be obtained.
Although not illustrated in FIG. 30, the wavelength conversion
layer 524' may not be separately provided and may have a structure
in which phosphor materials are distributed in the transparent
support substrate 525.
[0283] Before the transparent support substrate 525 is adhered and
before the graded index layer 521 is adhered, the wavelength
conversion layer 524' may be formed by coating wavelength
conversion materials on a bottom surface of the transparent support
substrate 525 through a simple process such as a spray coating
process or a spin coating process. The wavelength conversion layer
524' may be formed on the bottom surface of the transparent support
substrate 525 by using a method of attaching a sheet such as a
phosphor film or a ceramic phosphor.
[0284] FIG. 31 is a cross-sectional view of a semiconductor light
emitting device 500c, according to another example embodiment of
the inventive concept.
[0285] Referring to FIG. 31, the semiconductor light emitting
device 500c of FIG. 31 may be substantially identical to the
semiconductor light emitting device 500 of FIG. 15A, except that
the transparent support substrate 525 is replaced with a
transparent support substrate 525a.
[0286] In the semiconductor light emitting device 500c, the top
surface of the transparent support substrate 525a on a light path
of light emitted by a light-emitting structure 515p may have a
semispherical shape. That is, the top surface of the transparent
support substrate 525a, from which light is emitted, may have a
semispherical shape.
[0287] Therefore, the transparent support substrate 525a may serve
as a lens. The semispherical shape of the transparent support
substrate 525a may be formed by etching the upper portions of the
transparent support substrates 525 according to the above-described
example embodiments.
[0288] FIG. 32 is a cross-sectional view of a semiconductor light
emitting device 500d, according to another example embodiment of
the inventive concept.
[0289] Referring to FIG. 32, the semiconductor light emitting
device 500d of FIG. 32 may be substantially identical to the
semiconductor light emitting device 500a of FIG. 29, except that a
lens layer 543 is further formed on a transparent support substrate
525 and an optical filter layer 526 is added.
[0290] The lens layer 543 of the semiconductor light emitting
device 500d may include a material having excellent light
transparency and heat resistance, such as silicone, epoxy, glass,
or plastic. The lens layer 543 may adjust an orientation angle of
light emitted through the top surface thereof by a convex or
concave lens structure. The lens layer 543 may include a resin
having a degree of transparency sufficient to transmit light
emitted from the light-emitting structure 515p with significantly
reduced loss. For example, the lens layer 543 may include an
elastic resin, silicone, an epoxy resin, or plastic.
[0291] As illustrated in FIG. 32, the top surface of the lens layer
543 may have a convex dome shape, but the inventive concept is not
limited thereto. Alternatively, the lens layer 543 may have an
aspherical and/or asymmetrical shape, a concave/convex portion may
be formed on the top surface of the lens layer 543. The lens layer
543 may be formed on the transparent support substrate 525 by, for
example, a spray coating process.
[0292] In the semiconductor light emitting device 500d, the optical
filter layer 526 may be further formed between the transparent
support substrate 525 and the lens layer 543. The optical filter
layer 526 may be configured in such a manner that it allows light
within a required wavelength band to be selectively transmitted
while allowing light in a non-required wavelength band to be
selectively blocked. For example, the optical filter layer 526 may
be an omnidirectional reflector (ODR) or a distributed Bragg
reflector (DBR). In this case, the optical filter layer 526 may be
formed by alternately forming two types of dielectric layers having
different refractive indices. Alternatively, the optical filter
layer 526 may include a material such as a dye.
[0293] In the example embodiment, the optical filter layer 526 may
serve to block unconverted light, for example, blue light, having
the first wavelength in order to increase a rate of light, for
example, green or red light, having the second wavelength converted
by the wavelength conversion material 524 contained in the
transparent adhesive layer 523', in finally emitted light.
[0294] In the example embodiment, the optical filter layer 526 is
illustrated as being disposed on the top surface of the transparent
support substrate 525, but it may also be arranged in a different
position, as necessary. For example, the optical filter layer 526
may be disposed between the transparent support substrate 525 and
the transparent adhesive layer 523'.
[0295] FIG. 33 is a cross-sectional view of a semiconductor light
emitting device 500e, according to another example embodiment of
the inventive concept.
[0296] Referring to FIG. 33, the semiconductor light emitting
device 500e of FIG. 33 may be substantially identical to the
semiconductor light emitting device 500 of FIG. 15A, except that a
support layer 545 fills a first through hole 527, first electrode
layers 537a_1 and 539a_1 and second electrode layers 537a_2 and
539a_2 have different shapes, and external connection terminals
547_1 and 547_2 are further formed on the bottom surfaces of the
first electrode layers 537a_1 and 539a_1 and the second electrode
layers 537a_2 and 539a_2.
[0297] In the semiconductor light emitting device 500e, the support
layer 545 may be formed on a bottom surface of a reflective layer
533p while filling the inside of the first through hole 527. A
bottom surface of the support layer 545 may have the same plane as
the bottom surfaces of the first electrode layers 537a_1 and 539a_1
and the second electrode layers 537a_2 and 539a_2. The support
layer 545 may also be formed on side surfaces of the first
electrode layers 537a_1 and 539a_1 and the second electrode layers
537a_2 and 539a_2. The support layer 545 may protect the reflective
layer 533p, the first electrode layers 537a_1 and 539a_1, and the
second electrode layers 537a_2 and 539a_2, and may facilitate the
handling of the semiconductor light emitting device 500e.
[0298] In the semiconductor light emitting device 500e, a first
barrier metal layer 1 constituting the first electrode layers
537a_1 and 539a_1 may not be formed to protrude over a bottom
surface of the reflective layer 533p, and a second pad bump metal
layer constituting the second electrodes 537a_2 and 539a_2 may be
partially formed on a bottom surface of the second barrier metal
layer 537a_2. As described above, the semiconductor light emitting
device 500e may include the first electrode layers 537a_1 and
539a_1 and the second electrode layers 537a_2 and 539a_2 in
different shapes.
[0299] The external connection terminals 547_1 and 547_2 may be
respectively formed on bottom surfaces of the first electrode
layers 537a_1 and 539a_1 and the second electrode layers 537a_2 and
539a 2. The external connection terminals 547_1 and 547_2 may be
formed for connection to an external device. The external
connection terminals 547_1 and 547_2 may protrude outwardly from
the first electrode layers 537a_1 and 539a_1 and the second
electrode layers 537a_2 and 539a_2. The shapes of the external
connection terminals 547_1 and 547_2 are not limited to the shape
illustrated in FIG. 33. For example, the external connection
terminals 547_1 and 547_2 may have a pillar shape such as a
rectangular pillar or a cylinder.
[0300] The external connection terminals 547_1 and 547_2 may be
solder bumps. The external connection terminals 547_1 and 547_2 may
include at least one selected from the group consisting of copper
(Cu), aluminium (Al), silver (Ag), tin (Sn), and gold (Au).
[0301] FIGS. 34 and 35 are cross-sectional views of a white light
source module including a semiconductor light emitting device,
according to an example embodiment of the inventive concept.
[0302] Referring to FIG. 34, a light source module 1100 for a
liquid crystal display (LCD) backlight may include a circuit board
1110 and an array of a plurality of white light-emitting devices
1100a mounted on the circuit board 1110. Conductive patterns
connected to the white light-emitting devices 1100a may be formed
on the circuit board 1110.
[0303] Each of the white light-emitting devices 1100a may be
configured such that a light-emitting device 1130 configured to
emit blue light is directly mounted on the circuit board 1110 by
using a chip-on-board (COB) method. The light-emitting device 1130
may be at least one of the above-described semiconductor light
emitting devices 50, 50a, 50b, 50c, 50d, 100, 500, 500a, 500b,
500c, 500d, and 500e according to the example embodiments. Each of
the white light-emitting device 1100a may exhibit a wide
orientation angle because a wavelength conversion unit (wavelength
conversion layer) 1150a is formed to have a semispherical shape
with a lens function. The wide orientation angle may contribute to
reducing a thickness or a width of an LCD display.
[0304] Referring to FIG. 35, a light source module 1200 for an LCD
backlight may include a circuit board 1110 and an array of a
plurality of white light-emitting devices 1100b mounted on the
circuit board 1110. Each of the white light-emitting devices 1100b
may include a blue light-emitting device 1130 mounted in a
reflection cup of a package body 1125, and a wavelength conversion
unit 1150b that encapsulates the blue light-emitting device 1130.
The light-emitting device 1130 may be at least one of the
above-described semiconductor light emitting devices 50, 50a, 50b,
50c, 50d, 100, 500, 500a, 500b, 500c, 500d, and 500e according to
the example embodiments.
[0305] If necessary, the wavelength conversion units 1150a and
1150b may include wavelength conversion materials 1152, 1154, and
1156 such as phosphors and/or quantum dots as described in
reference to FIGS. 34 and 35. A detailed description of the
wavelength conversion materials may be referred to in the
description above with reference to FIG. 14.
[0306] In addition, as in the semiconductor light emitting devices
50, 50a, 50b, 50c, 50d, 100, 500a, 500b, and 500d, in the case that
the semiconductor light emitting device itself has a wavelength
conversion element, the wavelength conversion element of the
semiconductor light emitting device may have a different type or a
different color of wavelength conversion material from those of the
wavelength conversion units 1150a and 1150b.
[0307] FIG. 36 is a schematic perspective view of a backlight unit
2000 including a semiconductor light emitting device, according to
an example embodiment of the inventive concept.
[0308] Referring to FIG. 36, the backlight unit 2000 may include a
light guide plate 2040 and light source modules 2010 on both sides
of the light guide plate 2040. In addition, the backlight unit 2000
may further include a reflective plate 2020 under the light guide
plate 2040. The backlight unit 2000 according to the present
example embodiment may be an edge-type backlight unit. According to
some example embodiments, the light source module 2010 may only be
provided on one side of the light guide plate 2040 or may be
additionally provided on the other side. The light source module
2010 may include a printed circuit board (PCB) 2001 and a plurality
of light sources 2005 mounted on the PCB 2001. The light source
2005 may be at least one of the above-described semiconductor light
emitting devices 50, 50a, 50b, 50c, 50d, 100, 500, 500a, 500b,
500c, 500d, and 500e according to the example embodiments.
[0309] FIGS. 37 to 39 are cross-sectional views of backlight units
2500, 2600, and 2700 including a semiconductor light emitting
device, according to an example embodiment of the inventive
concept.
[0310] In the backlight units 2500, 2600, and 2700, wavelength
conversion units 2550, 2650, and 2750 are not arranged in light
sources 2505, 2605, and 2705. The wavelength conversion units 2550,
2650, and 2750 are arranged in the backlight units 2500, 2600, and
2700 outside of the light sources 2505, 2605, and 2705 so as to
convert light. The light sources 2505, 2605, and 2705 may be at
least one of the above-described semiconductor light emitting
devices 50, 50a, 50b, 50c, 50d, 100, 500, 500a, 500b, 500c, 500d,
and 500e according to the example embodiments. The semiconductor
light emitting device 50, 50a, 50b, 50c, 50d, 100, 500a, 500b, or
500d may themselves have a wavelength conversion element. In this
case, the wavelength conversion element of the semiconductor light
emitting device may have a different type or a different color of
wavelength conversion material from those of the wavelength
conversion units 2550, 2650 and 2750. For example, the wavelength
conversion element may include a red phosphor, such as fluoride,
vulnerable to moisture, and the wavelength conversion units 2550,
2650, and 2750 spaced apart from the light sources 2505, 2605, and
2705 may include a different type of wavelength conversion
material, such as a green quantum dot.
[0311] The backlight unit 2500 of FIG. 37 is a direct-type
backlight unit and may include the wavelength conversion unit 2550,
a light source module 2510 under the wavelength conversion unit
2550, and a bottom case 2560 accommodating the light source module
2510. In addition, the light source module 2510 may include a PCB
2501 and a plurality of light sources 2505 mounted on the PCB
2501.
[0312] In the backlight unit 2500, the wavelength conversion unit
2550 may be on the bottom case 2560. Therefore, at least a part of
the light emitted by the light source module 2510 may be
wavelength-converted by the wavelength conversion unit 2550. The
wavelength conversion unit 2550 may be manufactured as a separate
film and may be integrated with a light diffusion plate (not
illustrated).
[0313] The backlight units 2600 and 2700 of FIGS. 38 and 39 are
edge-type backlight units and may include the wavelength conversion
unit 2650 and 2750, light guide plates 2640 and 2740, and
reflection units 2620 and 2720 and light sources 2605 and 2705
arranged on one side of the light guide plates 2640 and 2740. The
light emitted by the light sources 2605 and 2705 may be guided
inside the light guide plates 2640 and 2740 by the reflection units
2620 and 2720. In the backlight unit 2600 of FIG. 38, the
wavelength conversion unit 2650 may be arranged between the light
guide plate 2640 and the light source 2605. In the backlight unit
2700 of FIG. 39, the wavelength conversion unit 2750 may be on a
light emission surface of the light guide plate 2740.
[0314] The wavelength conversion units 2550, 2650, and 2750 may
include typical phosphors. In particular, QD phosphors may be used
for supplementing characteristics of QDs vulnerable to moisture or
heat from the light source.
[0315] FIG. 40 is an exploded perspective view of a display device
3000 including a semiconductor light emitting device, according to
an example embodiment of the inventive concept.
[0316] Referring to FIG. 40, the display device 3000 may include a
backlight unit 3100, an optical sheet 3200, and a display panel
3300 such as a liquid crystal panel. The backlight unit 3100 may
include a bottom case 3110, a reflection plate 3120, a light guide
plate 3140, and a light source module 3130 on at least one side of
the light guide plate 3140. The light source module 3130 may
include a PCB 3131 and a light source 3132.
[0317] In detail, the light source 3132 may be a side view type LED
mounted on a side adjacent to a light emission surface. The light
source 3132 may be at least one of the above-described
semiconductor light emitting devices 50, 50a, 50b, 50c, 50d, 100,
500, 500a, 500b, 500c, 500d, and 500e according to the example
embodiments. The optical sheet 3200 may be between the light guide
plate 3140 and the display panel 3300 and may include various types
of sheets, such as a diffusion sheet, a prism sheet, or a
protection sheet.
[0318] The display panel 3300 may display an image by using light
emitted from the optical sheet 3200. The display panel 3300 may
include an array substrate 3320, a liquid crystal layer 3330, and a
color filter substrate 3340. The array substrate 3320 may include
pixel electrodes arranged in matrix form, thin film transistors
configured to apply a driving voltage to the pixel electrodes, and
signal lines configured to operate the thin film transistors.
[0319] The color filter substrate 3340 may include a transparent
substrate, a color filter, and a common electrode. The color filter
may include filters configured to selectively transmit light having
a specific wavelength in white light emitted by the backlight unit
3100. The liquid crystal layer 3330 may be rearranged by an
electric field formed between the pixel electrode and the common
electrode and adjust an optical transmittance. The light, of which
the optical transmittance is adjusted, may display an image while
passing through the color filter of the color filter substrate
3340. The display panel 3300 may further include a driving circuit
configured to process an image signal.
[0320] According to the present example embodiment, since the
display device 3000 uses the light source 3132 configured to emit
blue light, green light, and red light having a relatively narrow
full width at half maximum, the emitted light may implement blue,
green, and red colors having a high color purity after passing
through the color filter substrate 3340.
[0321] FIG. 41 is a perspective view of a flat-panel lighting
apparatus 4100 including a semiconductor light emitting device,
according to an example embodiment of the inventive concept.
[0322] Referring to FIG. 41, the flat-panel lighting apparatus 4100
may include a light source module 4110, a power supply 4120, and a
housing 4030. According to the present example embodiment, the
light source module 4110 may include an LED array as a light
source. The light source module 4110 may be at least one of the
above-described semiconductor light emitting devices 50, 50a, 50b,
50c, 50d, 100, 500, 500a, 500b, 500c, 500d, and 500e according to
the example embodiments. The power supply 4120 may include an LED
driver.
[0323] The light source module 4110 may include an LED array and
may be formed to have a flat shape as a whole. According to the
present example embodiment, the LED array may include an LED and
controller configured to store driving information of the LED.
[0324] The power supply 4120 may be configured to supply power to
the light source module 4110. The housing 4130 may form an
accommodation space for accommodating the light source module 4110
and the power supply 4120. The housing 4130 is formed to have a
hexahedral shape with one open side, but is not limited thereto.
The light source module 4110 may be arranged to emit light toward
the open side of the housing 4130.
[0325] FIG. 42 is an exploded perspective view of a lighting
apparatus 4200 including a semiconductor light emitting device,
according to an example embodiment of the inventive concept.
[0326] Referring to FIG. 42, the lighting apparatus 4200 may
include a socket 4210, a power supply 4220, a heat sink 4230, a
light source module 4240, and an optical unit 4250. According to
the present example embodiment, the light source module 4240 may
include an LED array, and the power supply 4220 may include an LED
driver.
[0327] The socket 4210 may be configured to accept an existing
lighting apparatus. Power may be supplied to the lighting apparatus
4200 through the socket 4210. The power supply 4220 may be
dissembled into a first power supply 4221 and a second power supply
4220. The heat sink 4230 may include an internal heat sink 4231 and
an external heat sink 4232. The internal heat sink 4231 may be
directly connected to the light source module 4240 and/or the power
supply 4220. The internal heat sink 4231 may transfer heat to the
external heat sink 4232. The optical unit 4250 may include an
internal optical unit (not illustrated) and an external optical
unit (not illustrated). The optical unit 4250 may be configured to
uniformly disperse light emitted by the light source module
4240.
[0328] The light source module 4240 may receive power from the
power supply 4220 and emit light to the optical unit 4250. The
light source module 4240 may include one or more semiconductor
light emitting devices 4241, a circuit board 4242, and controller
4243. The controller 4243 may store driving information of the
semiconductor light emitting devices 4241. The semiconductor light
emitting devices 4241 may be at least one of the above-described
semiconductor light emitting devices 50, 50a, 50b, 50c, 50d, 100,
500, 500a, 500b, 500c, 500d, and 500e according to the example
embodiments.
[0329] FIG. 43 is an exploded perspective view of a bar-type
lighting apparatus 4400 including a semiconductor light emitting
device, according to an example embodiment of the inventive
concept.
[0330] Referring to FIG. 43, the bar-type lighting apparatus 4400
may include a heat sink member 4401, a cover 4427, a light source
module 4421, a first socket 4405, and a second socket 4423. A
plurality of heat sink fins 4450 and 4409 having a concave/convex
shape may be formed on internal or external surfaces of the heat
sink member 4401. The heat sink fins 4450 and 4409 may be designed
to have various shapes and intervals. A support 4413 having a
protruding shape may be formed inside the heat sink member 4401.
The light source module 4421 may be fixed to the support 4413.
Locking protrusions 4411 may be formed on both ends of the heat
sink member 4401.
[0331] Locking grooves 4429 may be formed in the cover 4427. The
locking protrusions 4411 of the heat sink member 4401 may be hooked
to the locking grooves 4429. The positions of the locking grooves
4429 may be exchanged with the positions of the locking protrusions
4411.
[0332] The light source module 4421 may include an LED array. The
light source module 4421 may include a PCB 4419, a light source
4417, and a controller 4415. The controller 4415 may store driving
information of the light source 4417. Circuit wirings may be formed
on the PCB 4419 so as to operate the light source 4417. In
addition, the light source module 4421 may include components for
operating the light source 4417. The light source 4417 may be at
least one of the above-described semiconductor light emitting
devices 50, 50a, 50b, 50c, 50d, 100, 500, 500a, 500b, 500c, 500d,
and 500e according to the example embodiments.
[0333] The first and second sockets 4405 and 4423 may be provided
as a pair of sockets and may be connected to both ends of a
cylindrical cover unit including the heat sink member 4401 and the
cover 4427. For example, the first socket 4405 may include an
electrode terminal 4403 and a power supply 4407, and the second
socket 4423 may include a dummy terminal 4425. In addition, an
optical sensor module and/or a communications module may be
embedded into the first socket 4405 or the second socket 4423. For
example, the optical sensor module and/or the communications module
may be embedded into the second socket 4423 in which the dummy
terminal 4425 is arranged. As another example, the optical sensor
module and/or the communications module may be embedded into the
first socket 4405 in which the electrode terminal 4403 is
arranged.
[0334] FIG. 44 is an exploded perspective view of a lighting
apparatus 4500 including a semiconductor light emitting device,
according to an example embodiment of the inventive concept.
[0335] The lighting apparatus 4500 of FIG. 44 differs from the
lighting apparatus 4200 of FIG. 42 in that a reflection plate 4310
and a communications module 4320 are provided on a light source
module 4240. The reflection plate 4310 may uniformly disperse light
from the light source in a lateral direction and a rearward
direction so as to reduce glare.
[0336] The communications module 4320 may be mounted on the
reflection plate 4310, and a home network communication may be
performed through the communications module 4320. For example, the
communications module 4320 may be a wireless communications module
using ZigBee.RTM., Wi-Fi, or Li-Fi, and control an indoor or
outdoor lighting apparatus, such as on/off operations or brightness
adjustment of the lighting apparatus through a smartphone or a
wireless controller. In addition, electronic appliances and vehicle
systems, such as TVs, refrigerators, air conditioners, doorlock
systems, vehicles, may be controlled through a Li-Fi communications
module using a wavelength of visible light in the indoor or outdoor
lighting apparatus. The reflection plate 4310 and the
communications module 4320 may be covered by the cover 4330.
[0337] FIG. 45 is a diagram illustrating an indoor lighting control
network system 5000 including a semiconductor light emitting
device, according to an example embodiment of the inventive
concept.
[0338] Referring to FIG. 45, the indoor lighting control network
system 5000 may be a composite smart lighting-network system in
which illumination technology using an LED, Internet of Things
(IoT) technology and wireless communications technology converge.
The network system 5000 may be implemented using various lighting
apparatuses and wired/wireless communication devices, and may be
implemented using a sensor, a controller, a communications device,
and software for network control and maintenance.
[0339] The network system 5000 may be applied to a closed space
defined in buildings such as offices, an open space such as parks
or streets, and the like. The network system 5000 may be
implemented based on an IoT environment so as to collect, process,
and provide a variety of information to users.
[0340] An LED lamp 5200 included in the network system 5000 may
receive information regarding an ambient environment from a gateway
5100 and control illumination of the LED lamp 5200 itself.
Furthermore, the LED lamp 5200 may check and control the operating
states of other devices 5300 to 5800 included in the IoT
environment based on a visible light communications function of the
LED lamp 5200. The LED lamp 5200 may be at least one of the
above-described semiconductor light emitting devices 50, 50a, 50b,
50c, 50d, 100, 500, 500a, 500b, 500c, 500d, and 500e according to
the example embodiments. For example, the LED lamp 5200 may be at
least one of the lighting apparatuses 4100, 4200, 4400, and 4500
illustrated in FIGS. 41 to 44.
[0341] The network system 5000 may include the gateway 5100
configured to process data transmitted and received in accordance
with different communications protocols, the LED lamp 5200
communicably connected to the gateway 5100 and including an LED,
and a plurality of devices 5300 to 5800 communicably connected to
the gateway 5100 in accordance with various wireless communication
schemes. In order to implement the network system 5000 based on the
IoT environment, the devices 5300 to 5800, including the LED lamp
5200, may include at least one communications module. According to
the present example embodiment, the LED lamp 5200 may be
communicably connected to the gateway 5100 by a wireless
communications protocol such as Wi-Fi, ZigBee.RTM., or Li-Fi. To
this end, the LED lamp 5200 may include at least one lamp
communications module 5210.
[0342] The network system 5000 may be applied to a closed space
such as homes or offices, an open space such as parks or streets,
and the like. In a case where the network system 5000 is applied to
the home, the plurality of devices 5300 to 5800, which are included
in the network system 5000 and communicably connected to the
gateway 5100 based on the IoT technology, may include electronic
appliances 5300, a digital doorlock 5400, a garage doorlock 5500, a
lighting switch 5600 installed on a wall, a router 5700 for
relaying a wireless communication network, and mobile devices 5800
such as smartphones, tablets, or laptop computers.
[0343] In the network system 5000, the LED lamp 5200 may determine
the operating states of the various devices 5300 to 5800 or
automatically control the illumination of the LED lamp 5200 itself
according to the ambient environment and conditions by using the
wireless communication network (e.g., ZigBee.RTM., Wi-Fi, Li-Fi,
etc.) installed in a home. In addition, the LED lamp 5200 may
control the devices 5300 to 5800 included in the network system
5000 through the Li-Fi communication using the visible light
emitted by the LED lamp 5200.
[0344] The LED lamp 5200 may automatically control the illumination
of the LED lamp 5200 based on the information about the ambient
environment, transmitted from the gateway 5100 through the lamp
communications module 5210, or the information about the ambient
environment, collected from the sensor mounted on the LED lamp
5200. For example, the brightness of the LED lamp 5200 may be
automatically adjusted according to a type of a TV program viewed
on the TV 5310 or a screen brightness of the TV 5310. To this end,
the LED lamp 5200 may receive operation information of the TV 5310
from the lamp communications module 5210 connected to the gateway
5100. The lamp communications module 5210 may be integrally
modularized with the sensor and/or the controller included in the
LED lamp 5200.
[0345] For example, when a television (TV) program viewed on a TV
is a drama, the LED lamp 5200 may lower a color temperature to
12,000K or less (e.g., 5,000K) and adjust a color sense according
to a preset value, thus creating a cozy atmosphere. On the other
hand, when a TV program is a comedy program, the LED lamp 5200 may
increase a color temperature to 5,000K or more according to a set
value so as to be adjusted to bluish white light.
[0346] In addition, after elapse of a predetermined time after the
digital doorlock 5400 has been locked in such a state that there is
no person at home, it is possible to prevent electricity wastage by
turning off the turned-on LED lamp 5200. Alternatively, in a case
where a security mode is set through the mobile device 5800 or the
like, when the digital doorlock 5400 is locked in such a state that
there is no person at home, the LED lamp 5200 may maintain the
turned-on state.
[0347] The operation of the LED lamp 5200 may be controlled
according to information about the ambient environment, collected
through various sensors connected to the network system 5000. For
example, in a case where the network system 5000 is implemented in
a building, it is possible to turn on or off the illumination by
combining a lighting apparatus, a position sensor, and a
communications module within the building, or provide collected
information in real time, thus enabling efficient facility
management or efficient utilization of unused space. Since the
lighting apparatus such as the LED lamp 5200 is usually arranged in
almost all spaces of each floor in the building, a variety of
information about the building may be collected through a sensor
integrally provided with the LED lamp 5200, and the collected
information may be used for facility management and utilization of
unused spaces.
[0348] On the other hand, by combining the LED lamp 5200 with an
image sensor, a storage device, the lamp communications module
5210, or the like, the LED lamp 5200 may be used as a device
capable of maintaining building security or sensing and
counteracting emergency situations. For example, when a smoke or
temperature sensor is attached to the LED lamp 5200, it is possible
to promptly detect an outbreak of fire, thus minimizing fire
damage. In addition, it is possible to adjust the brightness of the
lighting apparatus, save energy, and provide a pleasant
illumination environment, taking into consideration outside weather
or an available amount of sunlight.
[0349] As described above, the network system 5000 may be applied
to a closed space such as homes, offices, or buildings, an open
space such as parks or streets, and the like. In a case where the
network system 5000 is intended to be applied to an open space
without physical limitations, it may be relatively difficult to
implement the network system 5000 due to a distance limitation of
wireless communications and a communication interference caused by
various obstacles. By mounting the sensors and the communications
modules on various lighting apparatuses and using the lighting
apparatuses as information collection units and communication relay
units, the network system 5000 may be more efficiently implemented
in the open environments.
[0350] FIG. 46 is a diagram illustrating a network system 6000
including a semiconductor light emitting device according to an
example embodiment of the inventive concept.
[0351] Specifically, FIG. 46 illustrates the network system 6000
applied to an open space. The network system 6000 may include a
communications connecting device 6100, a plurality of lighting
apparatuses 6120 and 6150 installed at predetermined intervals and
communicably connected to the communications connecting device
6100, a server 6160, a computer 6170 configured to manage the
server 6160, a communications base station 6180, a communications
network 6190 configured to connect communicable devices, and a
mobile device 6200.
[0352] The plurality of lighting apparatuses 6120 and 6150
installed in open external spaces such as streets or parts may
include smart engines 6130 and 6140, respectively. Each of the
smart engines 6130 and 6140 may include an LED configured to emit
light, a driver configured to drive the LED, a sensor configured to
collect information about an ambient environment, and a
communications module. The LEDs included in the smart engine 6130
and 6140 may be at least one of the above-described semiconductor
light emitting devices 50, 50a, 50b, 50c, 50d, 100, 500, 500a,
500b, 500c, 500d, and 500e according to the example
embodiments.
[0353] The communications module may enable the smart engines 6130
and 6140 to communicate with other peripheral devices in accordance
with the communications protocol such as Wi-Fi, ZigBee.RTM., or
Li-Fi.
[0354] For example, one smart engine 6130 may be communicably
connected to the other smart engine 6140. In this case, a Wi-Fi
mesh may be applied to the communications between the smart engines
6130 and 6140. At least one smart engine 6130 may be connected to
the communications connecting device 6100 connected to the
communications network 6190 by a wired/wireless communications. In
order to increase the efficiency of communications, the plurality
of smart engines 6130 and 6140 may be grouped into one group and be
connected to one communications connecting device 6100.
[0355] The communications connecting device 6100 may be an access
point (AP) capable of performing wired/wireless communications and
may relay communications between the communications network 6190
and other devices. The communications connecting device 6100 may be
connected to the communications network 6190 by at least one of the
wired/wireless communications schemes. For example, the
communications connecting device 6100 may be mechanically
accommodated in one of the lighting apparatuses 6120 and 6150.
[0356] The communications connecting device 6100 may be connected
to the mobile device 6200 through the communications protocol such
as Wi-Fi. A user of the mobile device 6200 may receive information
about the ambient environment, collected by the plurality of smart
engines 6130 and 6140, through the communications connecting device
connected to the smart engine 6130 of the adjacent lighting
apparatus 6120. The information about the ambient environment may
include local traffic information, weather information, and the
like. The mobile device 6200 may be connected to the communications
network 6190 through the communications base station 6180 by a
wireless cellular communications scheme such as a 3G or 4G
communications scheme.
[0357] On the other hand, the server 6160 connected to the
communications network 6190 may receive information collected by
the smart engines 6130 and 6140 respectively mounted on the
lighting apparatuses 6120 and 6150 and may monitor the operating
states of the lighting apparatuses 6120 and 6150. In order to
manage the lighting apparatuses 6120 and 6150 based on the
monitoring result of the operating states of the lighting
apparatuses 6120 and 6150, the server 6160 may be connected to the
computer 6170 that provides the management system. The computer
6170 may execute software capable of monitoring and managing the
operating states of the lighting apparatuses 6120 and 6150,
especially the smart engines 6130 and 6140.
[0358] FIG. 47 is a block diagram illustrating a communications
operation between a smart engine 6130 of a lighting apparatus 6120
and a mobile device 6200, including a semiconductor light emitting
device according to an example embodiment of the inventive
concept.
[0359] Specifically, FIG. 47 is a block diagram illustrating a
communications operation between the smart engine 6130 of the
lighting apparatus 6120 of FIG. 46 and the mobile device 6200 via
the visible light wireless communications. Various communications
schemes may be applied for transmitting information collected by
the smart engine 6130 to the mobile device 6200 of the user.
[0360] Through the communications connecting device (6100 of FIG.
46) connected to the smart engine 6130, the information collected
by the smart engine 6130 may be transmitted to the mobile device
6200, or the smart engine 6130 and the mobile device 6200 may be
directly communicable connected to each other. The smart engine
6130 and the mobile device 6200 may communicate directly with each
other through the visible light wireless communications
(Li-Fi).
[0361] The smart engine 6130 may include a signal processor 6510, a
controller 6520, an LED driver 6530, a light source 6540, and a
sensor 6550. The mobile device 6200, connected to the smart engine
6130 through the visible light wireless communications, may include
a controller 6410, a light receiver 6420, a signal processor 6430,
a memory 6440, and an input/output module 6450.
[0362] The visible light wireless communications (Li-Fi) technology
is a wireless communications technology that wirelessly transmits
information by using light of a visible light wavelength the human
may recognize with his/her eyes. The visible light wireless
communications technology differs from the existing wired optical
communications technology and infrared wireless communications in
that the light of the visible light wavelength, for example, a
specific frequency of visible light from the light emitting device
or the lighting apparatus, is used, and differs from the wired
optical communications technology in that communications
environment is a wireless environment. Contrary to the RF wireless
communications technology, the visible light wireless
communications technology may freely be used without regulation or
permission in terms of frequency use. In addition, the visible
light wireless communications technology has excellent physical
security and has differentiation that enable a user to confirm a
communications link with his/her eyes. Furthermore, the visible
light wireless communications technology is a convergence
technology that is capable of simultaneously obtaining the unique
purpose of the light source and the communications function.
[0363] The signal processor 6510 of the smart engine 6130 may
process data to be transmitted and received through the visible
light wireless communications. For example the signal processor
6510 may process information collected by the sensor 6550 into data
and transmit the data to the controller 6520. The controller 6520
may control the operations of the signal processor 6510 and the LED
driver 6530. In particular, the controller 6520 may control the
operation of the LED driver 6530 based on the data transmitted by
the signal processor 6510. The LED driver 6530 may transmit the
data to the mobile device 6200 by turning on the light source 6540
according to a control signal transmitted by the controller
6520.
[0364] The mobile device 6200 may include the light receiver 6420
configured to recognize visible light including data, as well as
the controller 6410, the memory 6440 configured to store data, the
input/output module 6450 including a display, a touch screen, and
an audio output unit, and the signal processor 6430. The light
receiver 6420 may detect visible light and convert the detected
visible light into an electrical signal. The signal processor 6430
may decode data included in the electrical signal. The controller
6410 may store the decoded data output from the signal processor
6430 in the memory 6440, or may output the decoded data through the
input/output module 6450 so as to allow the user to recognize the
decoded data.
[0365] FIG. 48 is a block diagram of a smart lighting system 7000
including a semiconductor light emitting device, according to an
example embodiment of the inventive concept.
[0366] Referring to FIG. 48, the smart lighting system 7000 may
include an illumination module 7100, a sensor module 7200, a server
7300, a wireless communications module 7400, a controller 7500, and
an information storage device 7600. The illumination module 7100
may include one or more lighting apparatuses installed in a
building and there is no limitation to a type of the lighting
apparatus. Examples of the lighting apparatus may include basic
illuminations for a living room, a room, a balcony, a bathroom,
stairs, and a front door, a mood illumination, a stand
illumination, and a decorative illumination. The lighting apparatus
may be at least one of the above-described semiconductor light
emitting devices 50, 50a, 50b, 50c, 50d, 100, 500, 500a, 500b,
500c, 500d, and 500e according to the example embodiments. For
example, the lighting apparatuses may be at least one of the
lighting apparatuses 4100, 4200, 4400, and 4500 illustrated in
FIGS. 41 to 44.
[0367] The sensor module 7200 may detect illumination states
related to the turn-on/off of each lighting apparatus and the
intensity of the illumination, output a signal corresponding to the
detected illumination state, and transmit the signal to the server
7300. The sensor module 7200 may be provided in the building where
the lighting apparatus is installed. One or more sensors module
7200 may be at a position where the illumination states of all the
lighting apparatuses controlled by the smart lighting system 7000
are detectable, or may be provided at each of the lighting
apparatuses.
[0368] The information about the illumination state may be
transmitted to the server 7300 in real time, or may be transmitted
with a time difference based on predetermined time unit such as
minute unit or hour unit. The server 7300 may be installed inside
and/or outside the building. The server 7300 may receive a signal
from the sensor module 7200, collect information about the
illumination state, such as the turn-on/off of the lighting
apparatus within the building, group the collected information,
define an illumination pattern based on the grouped information,
and provide information about the defined illumination pattern to
the wireless communications module 7400. In addition, the server
7300 may serve as a medium that transmits a command received from
the wireless communications module 7400 to the controller 7500.
[0369] Specifically, the server 7300 may receive the information
about the illumination state of the building, detected and
transmitted by the sensor module 7200, and collect and analyze the
information about the illumination state. For example, the server
7300 may divide the collected information into various groups by
period, such as time, day, day of week, weekdays and weekends, a
preset specified day, a week, and a month. Then, the server 7300
may program a "defined illumination pattern" defined as an
illumination pattern of an average day unit, week unit, weekday
unit, weekend unit, and month unit based on the grouped
information. The "defined illumination pattern" may be periodically
provided to the wireless communications module 7400, or may be
received from the server 7300 in response to a request for
providing information when the user requests the information
regarding the illumination pattern.
[0370] In addition, apart from the defining of the illumination
pattern from the information regarding the illumination state
received from the sensor module 7200, the server 7300 may provide
the wireless communications module 7400 with a "normal illumination
pattern" programmed in advance by reflecting a normal illumination
state occurring at home. As in the case of the "defined
illumination pattern", the "normal illumination pattern" may be
periodically provided from the server 7300, or may be provided when
there is a request from a user. Only one server 7300 is illustrated
in FIG. 48, but two or more servers may be provided when necessary.
Optionally, the "normal illumination pattern" and/or the "defined
illumination pattern" may be stored in the information storage
device 7600. The information storage device 7600 may be a so-called
cloud that is accessible via a network.
[0371] The wireless communications module 7400 may select one of
the plurality of illumination patterns received from the server
7300 and/or the information storage device 7600 and transmit a
command signal for executing or stopping an "automatic illumination
mode" to the server 7300. The wireless communications module 7400
may be applied to various portable wireless communications devices
such as smartphones, tablet personal computers (PCs), personal
digital assistants (PDAs), notebook computers, or netbook
computers, which may be carried by the user of the smart lighting
system.
[0372] Specifically, the wireless communications module 7400 may
receive various defined illumination patterns from the server 7300
and/or the information storage device 7600, select necessary
patterns from the received illumination patterns, and transmit a
command signal to the server 7300 so as to execute the "automatic
illumination mode" to operate the illumination module 7100 in the
selected illumination pattern. The command signal may be
transmitted at a set execution time. Alternatively, after the
command signal is transmitted without defining a stop time, the
execution of the "automatic illumination mode" may be stopped by
transmitting a stop signal when necessary.
[0373] In addition, the wireless communications module 7400 may
further have a function of allowing the user to partially modify
the illumination pattern received from the server 7300 and/or the
information storage device 7600 or manipulate a new illumination
pattern when necessary. The modified or newly manipulated "user
setting illumination pattern" may be stored in the wireless
communications module 7400, may be automatically transmitted to the
server 7300 and/or the information storage device 7600, or may be
transmitted when necessary. In addition, the wireless
communications module 7400 may automatically receive the "defined
illumination pattern" and the "normal illumination pattern" from
the server 7300 and/or the information storage device 7600, or may
receive the "defined illumination pattern" and the "normal
illumination pattern" by transmitting a provision request signal to
the server 7300.
[0374] The wireless communications module 7400 may exchange a
necessary command or information signal with the server 7300 and/or
the information storage device 7600, and the server 7300 may serve
as a medium between the wireless communications module 7400, the
sensor module 7200, and the controller 7500. In this manner, the
smart lighting system may be operated.
[0375] The connection between the wireless communications module
7400 and the server 7300 may be performed using an application
program of the smartphone. That is, the user may instruct the
server 7300 to execute the "automatic illumination mode" through an
application program downloaded in the smartphone, or may provide
information regarding the user setting illumination pattern"
manipulated or modified by the user.
[0376] The information may be automatically provided to the server
7300 and/or the information storage device 7600 by the storing of
the "user setting illumination pattern", or may be provided by
performing a transmission operation. This may be determined as a
default of the application program, or may be selected by the user
according to an option.
[0377] The controller 7500 may receive the command signal of
executing or stopping the "automatic illumination mode" from the
server 7300, and control one or more lighting apparatuses by
executing the received command signal in the illumination module
7100. That is, the controller 7500 may control the turn-on/off or
the like of the lighting apparatuses included in the illumination
module 7100 according to the command signal from the server
7300.
[0378] In addition, the smart lighting system 7000 may further
include an alarm device 7700 in the building. The alarm device 7700
may give an alarm when there is an intruder in the building.
[0379] Specifically, in a case where the "automatic illumination
mode" is executed in the building in the absence of the user, when
there occurs an intrusion in the building and there occurs an
abnormal situation deviating from the set illumination pattern, the
sensor module 7200 may detect the abnormal situation and transmit
an alarm signal to the server 7300. The server 7300 may notify the
wireless communications module 7400 of the abnormal situation and
operate the alarm device 7700 in the building by transmitting a
signal to the controller 7500.
[0380] In addition, when the alarm signal is transmitted to the
server 7300, the server 7300 may directly notify a security company
of an emergency situation via the wireless communications module
7400 or a TCP/IP network.
[0381] As set forth above, according to example embodiments of the
inventive concept, a flip chip semiconductor light emitting device
having a transparent support substrate using, for example, glass
may be provided. The transparent adhesive layer is interposed
between the transparent support substrate and the light emitting
structure and the transparent support substrate may be provided on
the surface of the light emitting structure on which the
concavo-convex portion is formed. The transparent adhesive layer
may be configured to act as a refractive index matching layer, and
as a result, light extraction efficiency may be enhanced. The
transparent adhesive layer may include a wavelength conversion
material such as a phosphor to simplify a wavelength conversion
structure.
[0382] In the semiconductor light emitting device according to the
example embodiment, since the first electrode layers and the second
electrode layers provided below the light-emitting structure
function as electrode pads, the first electrode layers and the
second electrode layers may be directly mounted on an external
device or an external substrate in a flip-chip structure.
[0383] In the semiconductor light emitting device according to the
example embodiment, the light extraction efficiency may be improved
by forming the graded index layer on the light-emitting structure
or by forming the reflective layer on the surface of the first
conductivity type semiconductor layer of the light-emitting
structure or in the through hole formed in the light-emitting
structure.
[0384] The semiconductor light emitting device according to the
example embodiment may be completed by adhering the transparent
support substrate on the light-emitting structure by using the
transparent adhesive layer and removing the growth substrate. In
addition, in the semiconductor light emitting device according to
the example embodiment, after the through hole is formed in the
light-emitting structure by using the etch stop layer, the
electrode structure may be formed under the light-emitting
structure. Therefore, the semiconductor light emitting device
according to the example embodiment may reduce the manufacturing
costs by simplifying the manufacturing process.
[0385] While example embodiments have been shown and described
above, it will be apparent to those skilled in the art that
modifications and variations could be made without departing from
the scope of the inventive concept as defined by the appended
claims.
* * * * *