U.S. patent application number 14/447397 was filed with the patent office on 2016-03-10 for light emitting apparatus.
The applicant listed for this patent is LG INNOTEK CO., LTD.. Invention is credited to Kwang Ki Choi, Hwan Hee Jeong, Sang Youl Lee, June O. Song.
Application Number | 20160072031 14/447397 |
Document ID | / |
Family ID | 43639121 |
Filed Date | 2016-03-10 |
United States Patent
Application |
20160072031 |
Kind Code |
A9 |
Choi; Kwang Ki ; et
al. |
March 10, 2016 |
LIGHT EMITTING APPARATUS
Abstract
A light emitting device including a contact layer, a blocking
layer over the contact layer, a protection layer adjacent the
blocking layer, a light emitter over the blocking layer, and an
electrode layer coupled to the light emitter. The electrode layer
overlaps the blocking layer and protection layer, and the blocking
layer has an electrical conductivity that substantially blocks flow
of current from the light emitter in a direction towards the
contact layer. In addition, the protection layer may be conductive
to allow current to flow to the light emitter or non-conductive to
block current from flowing from the light emitter towards the
contact layer.
Inventors: |
Choi; Kwang Ki; (Seoul,
KR) ; Jeong; Hwan Hee; (Seoul, KR) ; Lee; Sang
Youl; (Seoul, KR) ; Song; June O.; (Seoul,
KR) |
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Applicant: |
Name |
City |
State |
Country |
Type |
LG INNOTEK CO., LTD. |
Seoul |
|
KR |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20140339590 A1 |
November 20, 2014 |
|
|
Family ID: |
43639121 |
Appl. No.: |
14/447397 |
Filed: |
July 30, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14049006 |
Oct 8, 2013 |
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14447397 |
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12964161 |
Dec 9, 2010 |
8610157 |
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14049006 |
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Current U.S.
Class: |
257/98 |
Current CPC
Class: |
H01L 33/58 20130101;
H01L 2224/48091 20130101; H01L 2924/0002 20130101; H01L 2924/12032
20130101; H01L 2924/00 20130101; H01L 2924/00014 20130101; H01L
2924/00 20130101; H01L 33/60 20130101; H01L 2924/0002 20130101;
H01L 2224/48091 20130101; H01L 33/38 20130101; H01L 2924/12032
20130101; H01L 33/44 20130101; H01L 33/62 20130101; H01L 33/20
20130101 |
International
Class: |
H01L 33/60 20060101
H01L033/60; H01L 33/44 20060101 H01L033/44; H01L 33/38 20060101
H01L033/38 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2009 |
KR |
10-2009-0121739 |
Dec 9, 2009 |
KR |
10-2009-0121740 |
Feb 3, 2010 |
KR |
10-2010-0010048 |
Claims
1. A light emitting device comprising: a conductive support
substrate; a metal layer including a recess and on the conductive
support substrate; a light emitting structure layer on the metal
layer; a protection layer provided at a periphery of the conductive
support substrate, and a portion of the protection layer is
provided between the metal layer and the light emitting structure
layer; and an electrode structure at least partially overlapping
the protection layer and disposed on the light emitting structure
layer, wherein the electrode structure includes: an outer electrode
including a first part and a second part, an inner electrode
provided in a region between the first part and the second part of
the outer electrode and extending to electrically connect the first
part of the outer electrode with the second part of the outer
electrode, and a pad electrically connected to at least one of the
first part or the second part of the outer electrode, wherein the
outer electrode includes an outer side surface and an inner side
surface with a width between the outer side surface and the inner
side surface, and wherein the outer side surface of the outer
electrode is within 50 .mu.m from an outermost side of a top of the
light emitting structure layer.
2. The light emitting device of claim 1, wherein the inner side
surface of the outer electrode is within 50 .mu.m from the
outermost side of the top of the light emitting structure
layer.
3. The light emitting device of claim 1, wherein a width of the
first part of the outer electrode is within a range of 15 .mu.m to
25 .mu.m.
4. The light emitting device of claim 3, wherein a width of the
second part of the outer electrode is different than the width of
the first part of the outer electrode.
5. The light emitting device of claim 4, wherein the width of the
second part of the outer electrode is within a range of 25 .mu.m to
35 .mu.m.
6. The light emitting device of claim 1, wherein the width of the
outer electrode is greater than a width of the inner electrode.
7. The light emitting device of claim 1, further comprising a
current blocking layer disposed in the recess of the metal
layer.
8. The light emitting device of claim 7, wherein a top surface of
the current blocking layer contacts a bottom surface of the light
emitting structure layer.
9. The light emitting device of claim 7, wherein a thickness of the
current blocking layer and a depth of the recess are substantially
same.
10. The light emitting device of claim 1, wherein the metal layer
has an uneven structure.
11. The light emitting device of claim 7, wherein the current
blocking layer has a width that is about 0.9.about.1.3 times a
width of the inner electrode.
12. The light emitting device of claim 1, wherein the metal layer
includes an ohmic layer, the ohmic layer contacting a side portion
of the protection layer.
13. The light emitting device of claim 1, wherein the metal layer
includes an ohmic layer and a reflective layer, the reflective
layer contacting a bottom portion of the protection layer and a
bottom portion of the ohmic layer.
14. The light emitting device of claim 7, wherein a portion of the
inner electrode at least partially overlaps the current blocking
layer.
15. The light emitting device of claim 1, wherein a top surface of
the metal layer contacts a bottom surface of the light emitting
structure layer.
16. The light emitting device of claim 1, wherein a bottom surface
of the protection layer contacts a top surface of the metal layer,
and wherein a side surface of the protection layer contacts a side
surface of the metal layer.
17. The light emitting device of claim 1, wherein a portion of the
inner electrode at least partially overlaps the recess of the metal
layer.
18. The light emitting device of claim 1, wherein the light
emitting structure layer includes an inclined side surface, and
wherein the inclined side surface of the light emitting structure
layer at least partially overlaps the protection layer.
19. The light emitting device of claim 1, wherein a portion of a
top surface of the protection layer is exposed from the inclined
side surface of the light emitting structure layer.
20. A light emitting device comprising: a conductive support
substrate; a metal layer including a recess and on the conductive
support substrate, the metal layer having an uneven structure; a
current blocking layer disposed in the recess of the metal layer; a
light emitting structure layer on the metal layer and having an
inclined side surface; a protection layer provided on an outer
periphery portion of the conductive support substrate, a portion of
the protection layer between the metal layer and the light emitting
structure layer; and an electrode structure at least partially
overlapping the protection layer and disposed on the light emitting
structure layer, wherein the electrode structure includes: an outer
electrode including a first part and a second part, an inner
electrode provided in a region between the first part and the
second part of the outer electrode and extending to electrically
connect the first part of the outer electrode with the second part
of the outer electrode, and a pad electrically connected to at
least one of the first part or the second part of the outer
electrode, wherein the outer electrode includes an outer side
surface and an inner side surface with a width between the outer
side surface and the inner side surface, and wherein the inner side
surface of the outer electrode is within 50 .mu.m from an outermost
side of a top of the light emitting structure layer.
21. The light emitting device of claim 20, wherein a width of the
first part of the outer electrode is within a range of 15 .mu.m to
25 .mu.m.
22. The light emitting device of claim 21, wherein a width of the
second part of the outer electrode is different than the width of
the first part of the outer electrode.
23. The light emitting device of claim 22, wherein the width of the
second part of the outer electrode is within a range of 25 .mu.m to
35 .mu.m.
24. The light emitting device of claim 20, wherein the width of the
outer electrode is greater than a width of the inner electrode.
25. The light emitting device of claim 20, wherein a portion of a
top surface of the protection layer is exposed from the inclined
side surface of the light emitting structure layer.
26. The light emitting device of claim 20, wherein a thickness of
the current blocking layer and a depth of the recess are
substantially same.
27. The light emitting device of claim 20, wherein the current
blocking layer has a width that is about 0.9.about.1.3 times a
width of the inner electrode.
28. The light emitting device of claim 20, wherein a bottom surface
of the protection layer contacts a top surface of the metal layer,
and wherein a side surface of the protection layer contacts a side
surface of the metal layer.
29. A light emitting device comprising: a conductive support
substrate; a metal layer including a recess and on the conductive
support substrate, the metal layer having an uneven structure; a
current blocking layer disposed in the recess of the metal layer; a
light emitting structure layer on the metal layer and having an
inclined side surface; a protection layer provided on an outer
periphery portion of the conductive support substrate, a portion of
the protection layer between the metal layer and the light emitting
structure layer, the inclined side surface of the light emitting
structure layer at least partially overlapping the protection
layer; and an electrode structure at least partially overlapping
the protection layer and disposed on the light emitting structure
layer, wherein the electrode structure includes: an outer electrode
including a first part and a second part, an inner electrode
provided in a region between the first part and the second part of
the outer electrode and extending to electrically connect the first
part of the outer electrode with the second part of the outer
electrode, and a pad electrically connected to at least one of the
first part or the second part of the outer electrode, wherein a
bottom surface of the protection layer contacts a top surface of
the metal layer, wherein a side surface of the protection layer
contacts a side surface of the metal layer, wherein the current
blocking layer has a width that is about 0.9.about.1.3 times a
width of the inner electrode, wherein the outer electrode includes
an outer side surface and an inner side surface with a width
between the outer side surface and the inner side surface, and
wherein the outer side surface of the outer electrode is within in
a range of 15 .mu.m to 35 .mu.m from an outermost side of a top of
the light emitting structure layer.
30. The light emitting device of claim 29, wherein a width of the
first part of the outer electrode is within a range of 15 .mu.m to
25 .mu.m.
31. The light emitting device of claim 30, wherein a width of the
second part of the outer electrode is different than the width of
the first part of the outer electrode.
32. The light emitting device of claim 31, wherein the width of the
second part of the outer electrode is within a range of 25 .mu.m to
35 .mu.m.
33. The light emitting device of claim 29, wherein the width of the
outer electrode is greater than a width of the inner electrode.
Description
[0001] This application is a continuation of co-pending application
Ser. No. 14/049,006 filed on Oct. 8, 2013, which is a continuation
of application Ser. No. 12/964,161 filed on Dec. 9, 2010, now U.S.
Pat. No. 8,610,157 and claims priority of Korean Patent
Applications No. 10-2009-0121739 filed on Dec. 9, 2009, No.
10-2009-0121740 filed on Dec. 9, 2009, and No. 10-2010-0010048
filed on Feb. 3, 2010, which are hereby incorporated by reference
in their entirety.
BACKGROUND
[0002] 1. Field
[0003] One or more embodiments described herein relate to emission
of light.
[0004] 2. Background
[0005] Light emitting diodes (LED) have advantages in terms of cost
and power consumption compared to fluorescent and incandescent
lamps. For this reason, LEDs are used in liquid crystal displays,
electric bulletin boards and street lamps. In spite of their
technological superiority, improvements are still needed.
BRIEF DESCRIPTION OF THE DRAWING
[0006] FIG. 1 is a diagram of a first embodiment of a light
emitting device.
[0007] FIGS. 2 to 10 are diagrams showing steps included in one
embodiment of a method of manufacturing a light emitting
device.
[0008] FIG. 11 is a diagram of a second embodiment of a light
emitting device.
[0009] FIG. 12 is a diagram of a third embodiment of a light
emitting device.
[0010] FIG. 13 is a diagram showing one example of planar-shape
electrodes that may be used in a light emitting device according to
any of the aforementioned embodiments.
[0011] FIG. 14 is a diagram of another example of planar-shape
electrodes that may be used in a light emitting device according to
the aforementioned embodiments.
[0012] FIG. 15 is a diagram of another example of planar-shape
electrodes that may be used in a light emitting device according to
the aforementioned embodiments.
[0013] FIG. 16 is a diagram of another example of planar-shape
electrodes that may be used in a light emitting device according to
the aforementioned embodiments.
[0014] FIG. 17 is a diagram of another example of planar-shape
electrodes that may be used in a light emitting device according to
the aforementioned embodiments.
[0015] FIG. 18 is a diagram of a comparative embodiment of an
electrode.
[0016] FIG. 19 is a diagram showing the electrode in FIG. 15.
[0017] FIG. 20 is a diagram comparing light output of a light
emitting device including the electrode of the embodiment in FIG.
13 with a light emitting device including the electrode of the
comparative embodiment shown in FIG. 18.
[0018] FIG. 21 is a diagram of an embodiment of a light emitting
device package including one of the aforementioned embodiments of
the light emitting device.
[0019] FIG. 22 is a diagram of an embodiment of a backlight unit
including the light emitting device package of FIG. 21 and/or one
of the aforementioned embodiments of the light emitting device.
[0020] FIG. 23 is a diagram of an embodiment of a lighting unit
including one of the aforementioned embodiments of the light
emitting device or device package.
DETAILED DESCRIPTION
[0021] FIG. 1 shows a first embodiment of a light emitting device
that includes a conductive support substrate 175, a bonding layer
170 on the conductive support substrate 175, a reflective layer 160
on the bonding layer 170, an ohmic contact layer 150 on the
reflective layer 160, a protection layer 140 at a periphery portion
on the bonding layer 170, a light emitting structure layer 135
producing light on the ohmic contact layer 150 and the protection
layer 140, and an electrode layer 115 on the light emitting
structure layer 135.
[0022] The conductive support substrate 175 supports the light
emitting structure layer 135 and supplies power to the light
emitting structure layer 135 together with the electrode 115. For
example, the conductive support substrate 175 may include at least
one of Cu, Au, Ni, Mo, or Cu--W and one or more carrier wafers such
as, for example, Si, Ge, GaAs, ZnO, SiC, GaN, Ga2O3.
[0023] The bonding layer 170 may be formed on the conductive
support substrate 175, at a location under reflective layer 160 and
protection layer 140. The bonding layer 170 is in contact with the
reflective layer 160, the ohmic contact layer 150, and the
protection layer 140 such that the reflective layer 160, the ohmic
contact layer 150, and the protection layer 140 are bonded to the
conductive support substrate 175.
[0024] The bonding layer 170 is formed to bond the conductive
support substrate 175. Therefore, the bonding layer 170 is not
necessarily formed, when the conductive support substrate 175 are
plated or deposited, such that the bonding layer 170 may be
selectively formed. The bonding layer 170 includes barrier metal or
bonding metal and, for example, may include at least one of Ti, Au,
Sn, Ni, Cr, Ga, In, Bi, Cu, Ag or Ta.
[0025] The reflective layer 160 may be formed on the bonding layer
170, and may serve to improve light extraction efficiency by
reflecting incident light from the light emitting structure layer
135. The reflective layer 160 may be made of metal or alloys which
include, for example, at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru,
Mg, Zn, Pt, Au or Hf. Further, the reflective layer 160 may be
formed in a multi-layer structure using metal or alloys and a light
transmissive conductive material, such as IZO, IZTO, IAZO, IGZO,
IGTO, AZO, or ATO. The reflective layer 160 is provided to increase
light efficiency and may not necessarily be formed.
[0026] The ohmic contact layer 150 may be formed on the reflective
layer 160 in ohmic contact with the second conductive semiconductor
layer 130 to allow power to be smoothly supplied to the light
emitting structure layer 135. The ohmic contact layer may be
formed, for example, of at least any one of ITO, IZO, IZTO, IAZO,
IGZO, IGTO, AZO, or ATO.
[0027] According to one embodiment, the ohmic contact layer 150 is
selectively made of a light transmissive layer and metal, and may
be implemented in one layer or a multi-layer structure from one or
more of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO
(indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO
(indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO
(aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc
oxide), IrOx, RuOx, RuOx/ITO, Ni, Ag, Ni/IrOx/Au, or
Ni/IrOx/Au/ITO.
[0028] The ohmic contact layer 150 is provided to smoothly inject
carriers into the second conductive semiconductor layer 130 and may
not be necessarily formed. For example, the material used for the
reflective layer 160 may be a material that is in ohmic contact
with the second conductive semiconductor layer 130. The carriers
that are injected into the second conductive semiconductor layer
130 may not be largely different from when the ohmic contact layer
150 is formed.
[0029] A current blocking layer (CBL) 145 may be formed in discrete
or individual sections between the ohmic contact layer 150 and the
second conductive semiconductor layer 130. The top of each section
of the current blocking layer 145 is in contact with the second
conductive semiconductor layer 130 and the bottom and sides of the
current blocking layer 145 is in contact with the ohmic contact
layer 150.
[0030] The current blocking layer 145 may at least partially
overlap the electrode layer 115, and serves to increase current
concentration in the light-emitting structure layer 135. This
current concentration function allows the distance between the
electrode layer 115 and the conductive support substrate 175 to be
small, thereby improving light emitting efficiency of the light
emitting device 100. Moreover, the current concentration function
of the current blocking layer 145 allows large amounts of current
to flow in the light emitting structure layer 135.
[0031] Each section of the current blocking layer 145 may have a
width that is 0.9.about.1.3 times the width of the electrode. If
the electrode layer is formed from a plurality of electrodes (e.g.,
115a and 115b), the widths of the sections of the current blocking
layer may be 0.9.about.1.3 times the width of one of electrodes
115a or 115b. According to one embodiment, the sections of the
current blocking layer 145 may have widths that is 1.1.about.1.3
times the width of the electrode layer, or one of the electrodes
115a or 115b in the case the electrode layer includes a plurality
of electrodes.
[0032] The current blocking layer 145 may be made of a material
that has less electrical conductivity than the reflective layer 160
or the ohmic contact layer 150, a material that is in Schottky
contact with the second conductive semiconductor layer 130, or an
electric insulation material For example, the current blocking
layer 145 may include at least one of ZnO, SiO2, SiON, Si3N4,
Al2O3, TiO2, Ti, Al, or Cr.
[0033] As shown in FIG. 1, the current blocking layer 145 is formed
between the ohmic contact layer 150 and the second conductive
semiconductor layer 130. However, in an alternative embodiment, the
current blocking layer may be formed between the reflective layer
160 and the ohmic contact layer 150. According to another
embodiment, a region where current has difficulty flowing may be
formed by applying plasma treatment to the second conductive
semiconductor layer 130, without forming the current blocking layer
145. In this embodiment, the plasma-treated region may be used as a
current blocking region performing a function like the current
blocking layer 145.
[0034] The protection layer 140 may be formed at a periphery
portion on the bonding layer 170. When bonding layer 170 is not
included, the protection layer 140 may be formed at a periphery of
the conductive support substrate 175.
[0035] The protection layer 140 can reduce deterioration in
reliability of the light emitting device 100 due to separation of
the interface between the light emitting structure layer 145 and
the bonding layer 170.
[0036] The protection layer 140 may be a conductive layer or a
non-conductive layer. A conductive protection layer may be formed
from a transparent conductive oxide film or may include at least
one of Ti, Ni, Pt, Pd, Rh, Ir, or W.
[0037] The transparent conductive oxide film, for example, may be
any one of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO
(indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO
(indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO
(aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc
oxide).
[0038] A non-conductive protection layer may be formed from any one
of a variety of non-conductive materials.
[0039] When included, the protection layer may prevent fragments
from being generated from the bonding layer 170, which may adhere
and cause an electrical short to form between second conductive
semiconductor layer 130 and active layer 120 or between active
layer 120 and a first conductive semiconductor layer 110, when
isolation etching is applied to divide the light emitting structure
layer 145 into unit chips in a chip separation process. For this
purpose, the protection layer may be made of a material that is
resistant to being broken or generating fragments.
[0040] If the protection layer has electrical conductivity
(conductive protection layer), current can be injected into the
light emitting structure layer 135 through the conductive
protection layer. Therefore, light can be effectively produced from
the active layer on the conductive protection layer around the
light emitting structure layer 135.
[0041] Further, the conductive protection layer can reduce the
operational voltage of the light emitting device by reducing the
increase of operational voltage due to the current blocking layer
145. The conductive protection layer may, for example, be made of
the same material as the ohmic contact layer 150.
[0042] As an alternative to a conductive protection layer, a
non-conductive protection layer may be used. This layer may be made
of a material having very low electrical conductivity. For example,
the non-conductive protection layer 140 may be made of a material
significantly smaller in electrical conductivity than the
reflective layer 160 or the ohmic contact layer 150, a material
that is in Schottky contact with the second conductive
semiconductor layer 130, or an electric insulation material.
Examples of such a non-conductive material include ZnO or SiO2.
[0043] The non-conductive protection layer may serve to increase
the distance between the bonding layer 170 and the active layer
120. Therefore, it is possible to reduce the possibility of
electric short between the bonding layer 170 and the active layer
120.
[0044] In addition, the non-conductive protection layer prevents
fragments from being generated from the bonding layer 170, which
may adhere to and cause an electrical short to form between second
conductive semiconductor layer 130 and an active layer 120 or
between the active layer 120 and a first conductive semiconductor
layer 110, when isolation etching is applied to divide the light
emitting structure layer 145 into unit chips in a chip separation
process.
[0045] Further, the non-conductive protection layer is made of a
material that is resistant to being broken or which forms fragments
or a material having electrical conductivity that does not cause an
electric short to form, even if it is slightly broken into a small
amount of fragments, in the isolation etching.
[0046] The light emitting structure layer 135 may be formed on the
ohmic contact layer 150 and the protection layer 140. The sides of
the light emitting structure layer 135 may be inclined in the
isolation etching to allow for separation into unit chips. The
inclined surface may at least partially overlap the protection
layer 140.
[0047] A portion of the top of the protection layer 140 may be
exposed by the isolation etching. Therefore, the protection layer
140 may be formed to overlap the light emitting structure layer 135
at a predetermined region and not to overlap the light emitting
structure layer 135 at another other region.
[0048] The first conductive semiconductor layer 110 may be an
n-type layer of a material having a composition formula,
InxAlyGa1-x-yN (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1,
0.ltoreq.x+y.ltoreq.1), for example, InAlGaN, GaN, AlGaN, AlInN,
InGaN, AlN, or InN.
[0049] The active layer 120 is a layer emitting light, using a band
gap difference of an energy band according to the material of the
active layer 120, when electrons (or holes) injected through the
first conductive semiconductor layer 110 combine with the holes (or
electrons) injected through the second conductive semiconductor
layer 130.
[0050] The active layer 120 may be formed in any one of a single
quantum well, a multi-quantum well (MQW), a quantum point, or
quantum line structure, but other structures are also possible.
[0051] According to one embodiment, the active layer is made of a
semiconductor material having the composition formula,
InxAlyGa1-x-yN (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1,
0.ltoreq.x+y.ltoreq.1). When the active layer 120 is formed in a
multi-quantum well structure, the active layer 120 may be formed by
stacking a plurality of well layers and a plurality of barrier
layers, for example, in the order of InGaN well layer/GaN barrier
layer.
[0052] A clad layer (not shown) doped with an n-type or p-type
dopant may be formed on and/or under the active layer 120, and may
be implemented by an AlGaN layer or an InAlGaN layer.
[0053] The second conductive semiconductor layer 130 may be
implemented by, for example, a p-type semiconductor layer selected
from a semiconductor material having the composition formula,
InxAlyGa1-x-yN (0.ltoreq.x.ltoreq.2, 0.ltoreq.y.ltoreq.1,
0.ltoreq.x+y.ltoreq.1), for example InAlGaN, GaN, AlGaN, InGaN,
AlInN, AlN, or InN, and may be doped with a p-type dopant, such as
Mg, Zn, Ca, Sr, or Ba.
[0054] The first conductive semiconductor layer 110 may be a p-type
semiconductor layer and the second conductive semiconductor layer
130 may include an n-type semiconductor layer.
[0055] Further, a third conductive semiconductor layer (not shown)
including an n-type or a p-type semiconductor layer may be formed
on the second conductive semiconductor layer 130. Accordingly, the
light emitting structure layer 135 may have at least any one of np,
pn, npn, or pnp junction structures. Further, the doping
concentration in the first conductive semiconductor layer 110 and
the second conductive semiconductor layer 130 may be uniform or
non-uniform. That is, the structure of the light emitting structure
layer 130 may be modified in various ways and is not limited to
those described herein.
[0056] The light emitting structure layer 135 including the first
conductive semiconductor layer 110, the active layer 120, and the
second conductive semiconductor layer 130 may be formed in various
structures and is not limited to the structures of the light
emitting structure layer 130 which are exemplified in the
illustrative embodiments described herein.
[0057] The electrode layer 115 is formed on the top of the light
emitting structure layer 135 and may be divided in a predetermined
pattern. A roughness pattern 112 may be formed on the top of the
first conductive semiconductor layer 110 to increase light
extraction efficiency. Accordingly, a roughness pattern may be
formed on top of the electrode layer 115.
[0058] More specifically, electrode layer 115 may be in contact
with the top of the first conductive semiconductor layer 110, and
may be formed by stacking at least one pad unit and at least one
branch-shaped electrode unit in the same or a different
structure.
[0059] The electrode layer 115 may include one or more outer
electrodes 115a, one or more an inner electrodes 115b, and a pad
unit (115c in FIG. 13). That is, the electrode unit may be composed
of the outer electrode(s) 115a and the inner electrode(s) 115b.
[0060] The electrode layer 115 may overlap the protection layer 140
and the current blocking layer 145, at least at a predetermined
portion. For example, the outer electrode 115a may perpendicularly
overlap the protection layer 140 and the inner electrode 115b may
perpendicularly overlap the current blocking layer 145. The outer
electrode 115a may perpendicularly overlap the protection layer
140, when the current blocking layer 145 is not formed.
[0061] Since the protection layer overlaps the electrode 115, when
the protection layer is a conductive protection layer, a large
amount of current may be allowed to flow in the active layer 120
above the conductive protection layer. Therefore, light is emitted
through a larger area from the active layer 120, such that the
light efficiency of the light emitting device can be increased.
Further, the operational voltage of the light emitting device 100
can be reduced.
[0062] When the protection layer 140 is a non-conductive protection
layer, a small amount of current flows in the active layer 120
above the non-conductive protection layer, such that light may not
be produced, and accordingly, the light efficiency of the light
emitting device 100 may be reduced. However, since the electrode
layer 115 is positioned where it overlaps the non-conductive
protection layer, more current may be allowed to flow in the active
layer 120 above the non-conductive protection layer. Therefore,
light is emitted through a larger area from the active layer 120,
such that the light efficiency of the light emitting device can be
increased.
[0063] A passivation layer 180 may be formed at least on the sides
of the light emitting structure layer 135. Further, the passivation
layer 180 may be formed on top of the first conductive
semiconductor layer 110 and the protection layer 140. The
passivation layer 180 may be made of, for example, SiO2, SiOx,
SiOxNy, Si3N4, or Al2O3 to electrically protect the light emitting
structure layer 135.
[0064] FIG. 13 shows one example of planar-shape electrodes that
may be included in the light emitting device. A cross-sectional
shape taken along the line I-I' is shown in FIG. 1. The electrode
layer containing the planar-shaped electrodes 115 is formed on the
first conductive semiconductor layer 110. The electrodes may
include outer electrode 115a that extend along the edge of the
first conductive semiconductor layer 110 and inner electrode 115b
that connects the first portion of the outer electrode 115a with
the second portion of the outer electrode 115a. The inner electrode
115b may be disposed inside a region surrounded by the outer
electrode 115a.
[0065] The outer electrode 115a may include a first outer electrode
115a1, a second outer electrode 115a2, a third outer electrode
115a3, and a fourth outer electrode 115a4. Further, the inner
electrode 115b may include a first inner electrode 115b1, a second
inner electrode 115b2, a third inner electrode 115b3, and a fourth
inner electrode 115b4.
[0066] The outer electrode 115a may be at least partially formed
within 50 .mu.m from the outermost side of the top of the first
conductive semiconductor layer 110, and may be in contact with the
passivation layer 180. For example, the first outer electrode
115a1, the second outer electrode 115a2, the third outer electrode
115a3, and fourth outer electrode 115a4 each may be at least
partially disposed within 50 .mu.m from the outermost side of the
top of the first conductive semiconductor layer 110.
[0067] The outer electrode 115a may be disposed in a rectangular
shape with four sides and four corners and includes the first outer
electrode 115a1 and the second outer electrode 115a2 which extend
in a first direction, and the third outer electrode 115a3 and the
fourth outer electrode 115a4 which extend in a second direction,
which is perpendicular to the first direction.
[0068] The pad unit 115c may include a first pad unit 115c1 and a
second pad unit 115c2, in which the first pad unit 115c1 may be
positioned at the joint of the first outer electrode 115a1 and the
third outer electrode 115a3 and the second pad unit 115c2 may be
positioned at the joint of the first outer electrode 115a1 and the
fourth outer electrode 115a4.
[0069] The inner electrode 115b includes the first inner electrode
115b1, the second inner electrode 115b2, the third inner electrode
115b3 which extend in the second direction and connect the first
outer electrode 115a1 with the second outer electrode 115a2, and
the fourth inner electrode 115b4 that extends in the first
direction and connects the third outer electrode 115a3 with the
fourth outer electrode 115a4, which extend in the second
direction.
[0070] The distance A between the first outer electrode 115a1 and
the fourth inner electrode 115b4 may be larger than the distance B
between the second outer electrode 115a2 and the fourth inner
electrode 115b4.
[0071] Further, the distance C between the third outer electrode
115a3 and the first inner electrode 115b1, the distance D between
the first inner electrode 115b1 and the second inner electrode
115b2, the distance E between the second inner electrode 115b2 and
the third inner electrode 115b3, and the distance F between the
third inner electrode 115b3 and the fourth outer electrode 115a4
may be substantially the same.
[0072] Further, the width of at least a part of the outer electrode
115a may be larger than the width of the inner electrode 115b
[0073] Further, the width of at least a part of the outer electrode
115a may be larger than the width of the other parts of the outer
electrode 115a. For example, the first outer electrode 115a1 may be
formed larger in width than the inner electrode 115b and the first
outer electrode 115a1 may be formed larger in width than the second
outer electrode 115a2.
[0074] Further, the width adjacent to the first outer electrode
115a1 in the widths of the third outer electrode 115a3 and the
fourth outer electrode 115a4 may be larger than the width adjacent
to the second outer electrode 115a2. For example, the outer
electrode 115a and the inner electrode 115b define a window-shaped
opening, in which the width of the outer electrode 115a which is
positioned at the wide portion of the opening may be larger than
the width of the outer electrode which is positioned at the narrow
portion of the opening.
[0075] The inner electrode 115b divides the inner region surrounded
by the outer electrode 115a into a plurality of regions. The region
that is adjacent to the first outer electrode 115a1, which has the
largest width, in the regions is larger in area than the region
that is adjacent to the second outer electrode 115a2 having a
smaller width.
[0076] Further, the inner electrode 115b may be formed smaller in
width than the outer electrode 115a. For example, the first outer
electrode 115a1, and the portions of the third outer electrode
115ta3 and the fourth outer electrode 115a4, which are adjacent to
the first outer electrode 115a1, may be formed to have a
25.about.35 .mu.m width, the second outer electrode 115a2, and the
portions of the third outer electrode 115a3 and the fourth outer
electrode 115a4, which are adjacent to the second outer electrode
115a2, may be formed to have a 15.about.25 .mu.m width, and the
inner electrode 115b may be formed to have a 5.about.15 .mu.m
width.
[0077] The electrode layer 115 of the light emitting device
according to the embodiment shown in FIG. 13 may be applied to the
light emitting structure layer 135 of which one side is
800.about.1200 .mu.m long. The light emission area may be reduced
by the electrode layer 115, when the length of at least one side is
less than 800 .mu.m, while current may not be effectively supplied
through the electrode layer 115, when the length of at least one
side if less than 1200 .parallel.m. For example, the electrode
layer 115 in FIG. 13 may be applied to the light emitting structure
layer 135, which lengths and widths of 1000 .mu.m.
[0078] The electrode layer 115 described above can reduce
resistance and allow current from effectively distributed, in
comparison with the area that the electrode 115 occupies.
[0079] FIG. 14 shows another example of planar-shape electrodes
that may be included in the light emitting device. The electrode
layer is formed on the first conductive semiconductor layer 110 and
may include outer electrode 115a that extends along the edge on top
of the first conductive semiconductor layer 110 and inner electrode
115b that connects the outer electrode 115a.
[0080] The outer electrode 115a includes a first outer electrode
115a1, a second outer electrode 115a2, a third outer electrode
115a3, and a fourth outer electrode 115a4. Further, the inner
electrode 115b may include a first inner electrode 115b1, a second
inner electrode 115b2, and a third inner electrode 115b3.
[0081] The outer electrode 115a may be at least partially formed
within 50 .mu.m from the outermost side of the first conductive
semiconductor layer 110, and may be in contact with the passivation
layer 180.
[0082] The outer electrode 115a may be disposed in a rectangular
shape with four sides and four corners and include the first outer
electrode 115a1 and the second outer electrode 115a2 which extend
in a first direction, and the third outer electrode 115a3 and the
fourth outer electrode 115a4 which extend in a second direction,
which is perpendicular to the first direction.
[0083] The pad unit 115c may include a first pad unit 115c1 and a
second pad unit 115c2, in which the first pad unit 115c1 may be
positioned at the joint of the first outer electrode 115a1 and the
third outer electrode 115a3 and the second pad unit 115c2 may be
positioned at the joint of the first outer electrode 115a1 and the
fourth outer electrode 115a4.
[0084] The inner electrode 115b includes first inner electrode
115b1 and second inner electrode 115b2 which extend in the second
direction and connect first outer electrode 115a1 with second outer
electrode 115a2, and third inner electrode 115b3 that extends in
the first direction and connects the third outer electrode 115a3
with the fourth outer electrode 115a4, which extend in the second
direction.
[0085] The distance A between the first outer electrode 115a1 and
the third inner electrode 115b3 may be larger than the distance B
between the second outer electrode 115a2 and the third inner
electrode 115b3.
[0086] Further, the distance C between the third outer electrode
115a3 and the first inner electrode 115b1, the distance D between
the first inner electrode 115b1 and the second inner electrode
115b2, and the distance E between the second inner electrode 115b2
and the fourth outer electrode 115a4 may be substantially the
same.
[0087] Further, the width of at least a portion of the outer
electrode 115a may be larger than the width of the inner electrode
115b.
[0088] Further, the width of at least a part of the outer electrode
115a may be larger than the width of the other parts of the outer
electrode 115a. For example, the first outer electrode 115a1 may be
formed larger in width than the inner electrode 115b and the first
outer electrode 115a1 may be formed larger in width than the second
outer electrode 115a2.
[0089] Further, the width adjacent to the first outer electrode
115a1 in the widths of the third outer electrode 115a3 and the
fourth outer electrode 115a4 may be larger than the width adjacent
to the second outer electrode 115a2.
[0090] The inner electrode 115b divides the inner region surrounded
by the outer electrode 115a into a plurality of regions. The region
that is adjacent to the first outer electrode 115a1, which has the
largest width, in the regions are larger in area than the region
that is adjacent to the second outer electrode 115a2.
[0091] The electrode layer 115 of the light emitting device shown
in FIG. 14 may be applied to the light emitting structure layer
135, of which one side is 800.about.1200 .mu.m long. The light
emission area may be reduced by the electrode 115, when the length
of at least one side is less than 800 .mu.m, while current may not
be effectively supplied through the electrode layer 115 when the
length of at least one side if less than 1200 .mu.m. For example,
the electrode layer 115 in FIG. 14 may be applied to the light
emitting structure layer 135, which lengths and widths of 1000
.mu.m.
[0092] The electrode 115 described above can reduce resistance and
allow current from effectively distributed, in comparison with the
area that the electrode 115 occupies.
[0093] FIG. 15 shows another example of planar-shape electrodes
that may be included in the light emitting device. The electrode
layer 115 is formed on the first conductive semiconductor layer 110
and may include outer electrode 115a that extends along the edge on
top of the first conductive semiconductor layer 110 and inner
electrode 115b that connect is the outer electrode 115a.
[0094] The outer electrode 115a includes a first outer electrode
115a1, a second outer electrode 115a2, a third outer electrode
115a3, and a fourth outer electrode 115a4. Further, the inner
electrode 115b may include a first inner electrode 115b1 and a
second inner electrode 115b2.
[0095] The outer electrode 115a may be at least partially formed
within 50 .mu.m from the outermost side of the first conductive
semiconductor layer 110, and may be in contact with the passivation
layer 180.
[0096] The outer electrode 115a may be disposed in a rectangular
shape with four sides and four corners and may include the first
outer electrode 115a1 and the second outer electrode 115a2 which
extend in a first direction, and the third outer electrode 115a3
and the fourth outer electrode 115a4 which extend in a second
direction, which is perpendicular to the first direction.
[0097] The pad unit 115c may include a first pad unit 115c1 and a
second pad unit 115c2, in which the first pad unit 115c1 may be
positioned at the joint of the first outer electrode 115a1 and the
third outer electrode 115a3 and the second pad unit 115c2 may be
positioned at the joint of the first outer electrode 115a1 and the
fourth outer electrode 115a4.
[0098] The inner electrode includes the first inner electrode 115b1
and the second inner electrode 115b2 which extend in the second
direction and connect the first outer electrode 115a1 and the
second outer electrode 115a2, which extend in the first
direction.
[0099] The distance C between the third outer electrode 115a3 and
the first inner electrode 115b1, the distance D between the first
inner electrode 115b1 and the second inner electrode 115b2, and the
distance E between the second inner electrode 115b2 and the fourth
outer electrode 115a4 may be substantially the same.
[0100] As described with reference to FIGS. 13 and 14, in the
electrode layer 115 shown in FIG. 15, the width of at least a part
of the outer electrode 115a may be larger than the width of the
inner electrode 115b, while the width of at least a part of the
outer electrode 115a may be larger than the other parts of the
outer electrode 115a. For example, the first outer electrode 115a1
may be formed larger in width than the inner electrode 115b and the
first outer electrode 115a1 may be formed larger in width than the
second outer electrode 115a2. As shown in FIG. 15, the outer
electrode 115a and the inner electrode 115b may be formed to have
the same width.
[0101] The electrode layer 115 of the light emitting device shown
in FIG. 15 may be applied to the light emitting structure layer
135, of which one side is 800.about.1200 .mu.m long. The light
emission area may be reduced by the electrode 115, when the length
of at least one side is less than 800 .mu.m, while current may not
be effectively supplied through the electrode layer 115, when the
length of at least one side if less than 1200 .mu.m. For example,
the electrode layer 115 shown in FIG. 15 may be applied to the
light emitting structure layer 135, which lengths and widths of
1000 .mu.m.
[0102] The electrode layer 115 described above can reduce
resistance and allow current from effectively distributed, in
comparison with the area that the electrode 115 occupies.
[0103] FIG. 16 shows another example of planar-shape electrodes
that may be included in the light emitting device. The electrode
layer 115 is formed on the first conductive semiconductor layer 110
and may include outer electrode 115a extending along the edge on
top of the first conductive semiconductor layer 110 and inner
electrode 115b connecting the outer electrode 115a with the outer
electrode 115a.
[0104] The outer electrode 115a includes a first outer electrode
115a1, a second outer electrode 115a2, a third outer electrode
115a3, and a fourth outer electrode 115a4.
[0105] The outer electrode 115a may be at least partially formed
within 50 .mu.m from the outermost side of the first conductive
semiconductor layer 110, and may be in contact with the passivation
layer 180.
[0106] The outer electrode 115a may be disposed in a rectangular
shape with four sides and four corners and may include the first
outer electrode 115a1 and the second outer electrode 115a2 which
extend in a first direction, and the third outer electrode 115a3
and the fourth outer electrode 115a4 which extend in a second
direction, which is perpendicular to the first direction.
[0107] The pad unit 115c may be positioned at the joint of the
first external electrode 115a1 and the inner electrode 115b. The
inner electrode 115b extends in the second direction and connects
the first outer electrode 115a1 with the second outer electrode
115a2, which extend in the first direction.
[0108] The distance C between the third outer electrode 115a3 and
the inner electrode 115b may be substantially the same as the
distance D between the inner electrode 115b and the fourth outer
electrode 115a4.
[0109] As described with reference to FIGS. 13 and 14, in the
electrode 115 shown in FIG. 16, the width of at least a part of the
outer electrode 115a may be larger than the width of the inner
electrode 115b, while the width of at least a part of the outer
electrode 115a may be larger than the other parts of the outer
electrode 115a.
[0110] For example, the first outer electrode 115a1 may be formed
larger in width than the inner electrode 115b and the first outer
electrode 115a1 may be formed larger in width than the second outer
electrode 115a2. As shown in FIG. 16, the outer electrode 115a and
the inner electrode 115b may be formed to have the same width.
[0111] The electrode layer 115 of the light emitting device in FIG.
16 may be applied to the light emitting structure layer 135 of
which one side is 400.about.800 .mu.m long. The light emission area
may be reduced by the electrode layer 115, when the length of at
least one side is less than 400 .mu.m, while current may not be
effectively supplied through the electrode layer 115 when the
length of at least one side if less than 800 .mu.m. For example,
the electrode 115 shown in FIG. 16 may be applied to the light
emitting structure layer 135, which lengths and widths of 600
.mu.m.
[0112] The electrode 115 described above can reduce resistance and
allow current from effectively distributed, in comparison with the
area that the electrode 115 occupies.
[0113] FIG. 17 shows another example of planar-shape electrodes
that may be used in the light emitting device. The electrode layer
115 is formed on the first conductive semiconductor layer 110 and
may include outer electrode 115a that extends along the edge on top
of the first conductive semiconductor layer 110 and inner electrode
115b that connect with the outer electrode 115a.
[0114] The outer electrode 115a includes a first outer electrode
115a1, a second outer electrode 115a2, a third outer electrode
115a3, and a fourth outer electrode 115a4. Further, the inner
electrode 115b may include a first inner electrode 115b1 and a
second inner electrode 115b2.
[0115] The outer electrode 115a may be at least partially formed
within 50 .mu.m from the outermost side of the first conductive
semiconductor layer 110, and may be in contact with the passivation
layer 180.
[0116] The outer electrode 115a may be disposed in a rectangular
shape with four sides and four corners and includes the first outer
electrode 115a1 and the second outer electrode 115a2 which extend
in a first direction, and the third outer electrode 115a3 and the
fourth outer electrode 115a4 which extend in a second direction,
which is perpendicular to the first direction.
[0117] The pad unit 115c may be positioned at the joint of the
first external electrode 115a1 and the first inner electrode
115b1.
[0118] The inner electrode 115b includes the first inner electrode
115b1 that extends in the second direction and connects the first
outer electrode 115a1 with the second outer electrode 115a2, and
the second inner electrode 115b2 that extends in the first
direction and connects the third outer electrode 115a3 with the
fourth outer electrode 115a4, which extend in the second
direction.
[0119] The distance A between the first outer electrode 115a1 and
the second inner electrode 115b2 may be larger than the distance B
between the second outer electrode 115a2 and the second inner
electrode 115b2.
[0120] Further, the distance C between the third outer electrode
115a3 and the first inner electrode 115b1 may be substantially the
same as the distance D between the first inner electrode 115b1 and
the fourth outer electrode 115a4.
[0121] As described with reference to FIGS. 13 and 14, in the
electrode layer 115 in FIG. 17, the width of at least a part of the
outer electrode 115a may be larger than the width of the inner
electrode 115b, while the width of at least a part of the outer
electrode 115a may be larger than the other parts of the outer
electrode 115a.
[0122] For example, the first outer electrode 115a1 may be formed
larger in width than the inner electrode 115b and the first outer
electrode 115a1 may be formed larger in width than the second outer
electrode 115a2. As shown in FIG. 17, the outer electrode 115a and
the inner electrode 115b may be formed to have the same width.
[0123] The inner electrode 115b divides the inner region surrounded
by the outer electrode 115a into a plurality of regions. The region
that is adjacent to the first outer electrode 115a1 in the regions
is larger in area than the region that is adjacent to the second
outer electrode 115a2.
[0124] The electrode layer 115 of the light emitting device in FIG.
17 may be applied to the light emitting structure layer 135 of
which one side is 400.about.800 .mu.m long. The light emission area
may be reduced by the electrode 115, when the length of at least
one side is less than 400 .mu.m, while current may not be
effectively supplied through the electrode 115, when the length of
at least one side if less than 800 .mu.m. For example, the
electrode 115 shown in FIG. 17 may be applied to the light emitting
structure layer 135, which lengths and widths of 600 .mu.m.
[0125] The electrode 115 described above can reduce resistance and
allow current from effectively distribution, compared to the area
that electrode 115 occupies.
[0126] FIGS. 18 and 19 show examples of light output in accordance
with arrangement of electrodes in a light emitting device according
to one or more of the aforementioned embodiments. More
specifically, an electrode according to a comparative arrangement
is shown in FIG. 18 and an electrode described with reference to
FIG. 15 is shown in FIG. 19.
[0127] The electrode layer 115 in FIG. 18 and the electrode layer
115 in FIG. 19 have substantially the same shape. However, the
electrode layer 115 according to the comparative arrangement in
FIG. 18 is disposed at a distance above 50 .mu.m from the outermost
side of the top of the first conductive semiconductor layer 110,
while the electrode 115 shown in FIG. 19 is at least partially
disposed within 50 .mu.m from the outermost side of the top of the
first conductive semiconductor layer 110, in contact with the
passivation layer 180.
[0128] According to an experiment, it could be seen that light
output of 282 mW was measured in the comparative arrangement in
FIG. 18 and light output of 304 mW was measured in the embodiment
in FIG. 19, such that the light output was improved by 8%, when
only the arrangement of electrodes 115 is changed, with the other
conditions kept the same.
[0129] FIG. 20 shows a comparison of light outputs of a light
emitting device including the electrode embodiment in FIG. 13 with
a light emitting device including the electrode of the comparative
arrangement in FIG. 18.
[0130] According to an experiment, it can be seen that the light
output of the light emitting device including the electrodes in
FIG. 13 is excellent, compared with the light output of the light
emitting device including the electrodes of the comparative
arrangement in FIG. 18, when the electrodes 115 are arranged as
illustrated in FIGS. 13 and 18, with the other conditions kept the
same.
[0131] FIG. 11 shows a second embodiment of a light emitting device
which has a structure similar to the light emitting device
according to the first embodiment. However, in the light emitting
device according to the second embodiment, the ohmic contact layer
150 extends to the sides of the light emitting device. That is, the
ohmic contact layer 150 is disposed on the sides and the bottom of
the protection layer 140, and the protection layer 140 and bonding
layer 170 are spaced by the ohmic contact layer 150.
[0132] FIG. 12 shows a third embodiment of a light emitting device
which has a structure similar to the light emitting device
according to the first embodiment. However, in the light emitting
device according to the third embodiment, the reflective layer 160
extends to the sides of the light emitting device.
[0133] That is, the reflective layer 160 is disposed on the bottoms
of the protection layer 140 and the ohmic layer 150, and the
protection layer 140 and the bonding layer 170 are spaced by the
ohmic contact layer 160. The protection layer 140 is partially
formed on the reflective layer 160. The reflective layer 160 can
increase light efficiency by more effectively reflecting the light
produced from the active layer 120, when being formed on the entire
top of the bonding layer 170. Though not shown, the ohmic contact
layer 150 and the reflective layer 160 may be disposed to extend to
the sides of the light emitting device.
[0134] FIGS. 2 to 10 show results produced by different steps
included in one embodiment of a method for manufacturing a light
emitting device. Referring to FIG. 2, the light emitting structure
layer 135 is formed on a growth substrate 101. The growth substrate
101 may be made of, for example, at least one of sapphire (Al2O3),
SiC, GaAs, GaN, ZnO, Si, GaP, InP, or Ge.
[0135] The light emitting structure layer 135 may be formed by
sequentially growing the first conductive semiconductor layer 110,
the active layer 120, and the second conductive semiconductor layer
130 on the growth substrate 101. The light emitting structure layer
135 may be formed by MOCVD (Metal Organic Chemical Vapor
Deposition), CVD (Chemical Vapor Deposition), PECVD
(Plasma-Enhanced Chemical Vapor Deposition), MBE (Molecular Beam
Epitaxy), and HVPE (Hydride Vapor Phase Epitaxy), and is not
limited thereto.
[0136] A buffer layer and/or an undoped nitride layer may be formed
between the light emitting structure layer 135 and the growth
substrate 101 to reduce a lattice constant difference.
[0137] Referring to FIG. 3, the protection layer 140 is formed on
the light emitting structure layer 135, corresponding to a unit
chip region. The protection layer may be formed around the unit
chip area by a mask pattern, and may be formed using various
deposition methods.
[0138] In particular, when the protection layer 140 is a conductive
protection layer and includes at least one of Ti, Ni, Pt, Pd, Rh,
Ir, or W, the protection layer 140 can be formed to have high
concentration by sputtering, such that it is not broken into
fragments in isolation etching.
[0139] Referring to FIG. 4, the current blocking layer 145 may be
formed on the second conductive layer 130. The current blocking
layer 145 may be formed by a mask pattern. For example, the current
blocking layer 145 may be formed by a mask pattern, after a SiO2
layer is formed on the second conductive semiconductor layer
130.
[0140] When the protection layer 140 is a non-conductive protection
layer, the protection layer 140 and the current blocking layer 145
may be made of the same material. In this case, it is possible to
simultaneously form the protection layer 140 and the current
blocking layer 145 in one process, not in separate processes.
[0141] For example, the protection layer 140 and the current
blocking layer 145 may be simultaneously formed by a mask pattern,
after a SiO2 layer is formed on the second conductive semiconductor
layer 130.
[0142] Referring to FIGS. 5 and 6, the ohmic contact layer 150 is
formed on the second conductive semiconductor layer 130 and the
current blocking layer 145, and then the reflective layer 160 may
be formed on the ohmic contact layer 150.
[0143] When the protection layer 150 is a conductive protection
layer, the ohmic contact layer 150 may be made of the same material
as the protection layer 140, in which the protection layer 140 and
the ohmic contact layer 150 may be simultaneously formed, after the
current blocking layer 145 is formed on the second conductive
semiconductor layer 130. The ohmic contact layer 150 and the
reflective layer may be formed, for example, using any one of
E-beam deposition, sputtering, or PECVD (Plasma Enhanced Chemical
Vapor Deposition).
[0144] The area where the ohmic contact layer 150 and the
reflective layer 160 are formed may be variously selected and the
light emitting devices according to the other embodiments described
with reference to FIGS. 11 and 12 may be formed in accordance with
the area where the ohmic contact layer 150 and/or the reflective
layer 160 are formed.
[0145] Referring to FIG. 7, the conductive support substrate 175 is
formed above the reflective layer 160 and the protection layer 140
with the bonding layer 170 therebetween. The bonding layer 170 is
in contact with the reflective layer 160, the ohmic contact layer
150, and the passivation layer 140 such that the bonding force can
be strengthened between reflective layer 160, the ohmic contact
layer 150, and the passivation layer 140.
[0146] The conductive support substrate 175 is attached to the
bonding layer 170. Although it is exemplified in the embodiment
that the conductive support substrate 175 is bonded by the bonding
layer 170, the conductive support substrate 175 may be plated or
deposited.
[0147] Referring to FIG. 8, the growth substrate 101 is removed
from the light emitting structure layer 135. The structure shown in
FIG. 7 is turned over in FIG. 8. The growth substrate 101 can be
removed by laser lift-off or chemical lift-off.
[0148] Referring to FIG. 9, the light emitting structure layer 135
is divided into a plurality of light emitting structure layers 135
by applying isolation etching to each unit chip. For example, the
isolation etching may be performed by dry etching, such as ICP
(Inductively Coupled Plasma).
[0149] Referring to FIG. 10, the passivation layer 180 is formed on
the protection layer 140 and the light emitting structure layer 135
and the passivation layer 180 is selectively removed such that the
top of the first conductive semiconductor layer 110 is exposed.
[0150] Further, a roughness pattern 112 is formed on the top of the
first conductive semiconductor layer 110 to improve light
extraction efficiency and the electrode 115 is formed on the
roughness pattern 112. The roughness pattern 112 may be formed by
wet etching or dry etching.
[0151] Further, a plurality of light emitting devices can be
manufactured by dividing the structure in unit chip regions, using
a chip separation process. The chip separation process may include,
for example, a braking process that separate the chips by applying
physical force with a blade, a laser scribing process that
separates the chips by radiating laser to the chip interfaces, and
an etching including wet etching and dry etching, but it is not
limited thereto.
[0152] FIG. 21 shows a cross-sectional view of one embodiment of a
light emitting device package that includes one or more light
emitting devices according to any of the aforementioned
embodiments.
[0153] Referring to FIG. 21, a light emitting device package
according to an embodiment includes a package body 10, a first
electrode 31 and a second electrode 32 which are installed at the
package body 10, a light emitting device 100 installed in the
package body 10 and electrically connect the first electrode 31
with the second electrode 32, and a molding member 40 covering the
light emitting device 100.
[0154] The package body 10 may include a silicon material, a
synthetic resin material, and a metal material, and may have a
cavity with inclined sides.
[0155] The first electrode 31 and the second electrode 32 are
electrically disconnected and supply power to the light emitting
device 100. Further, the first electrode 31 and the second
electrode 32 can increase light efficiency by reflecting light
produced from the light emitting device 100, and may function of
discharging heat generated from the light emitting device 100 to
the outside.
[0156] The light emitting device 100 may be installed on the
package body 10 or on the first electrode 31 and the second
electrode 32.
[0157] The light emitting device 100 may be electrically connected
with the first electrode 31 and the second electrode 32 by any one
of a wire way, a flip-chip way, and a die bonding way. Exemplified
in the embodiment, the light emitting device 100 is electrically
connected with the first electrode 31 by a wire 50 and electrically
connected with the second electrode 32 by direct contact.
[0158] The molding member 40 can protect the light emitting device
100 by covering the light emitting device 100. Further, fluorescent
substances may be included in the molding member 40 to change the
wavelength of light emitted from the light emitting device 100.
[0159] According to one embodiment, a plurality of light emitting
device packages are arrayed on the substrate, and a light guide
panel, a prism sheet, a diffusion sheet, and a fluorescent sheet,
which are optical components, may be disposed in the path of the
light emitted from the light emitting device packages. The light
emitting device package, the substrate, and the optical components
may function as a backlight unit or a lighting unit, and for
example, the light system may include a backlight unit, a lighting
unit, an indicator, a lamp, and a street lamp.
[0160] FIG. 22 shows one embodiment of a backlight unit 1100 that
includes a light emitting device or a light emitting device
package. The backlight unit 1100 shown in FIG. 22 is an example of
a lighting system and not limited thereto.
[0161] Referring to FIG. 22, the backlight unit 1100 may include a
bottom frame 1140, a light guide member 1120 disposed inside the
bottom frame 1140, and a light emitting module 1110 disposed at
least on one side or the bottom of the light guide member 1120.
Further, a reflective sheet 1130 may be disposed under the light
guide member 1120.
[0162] The bottom frame may be formed in a box shape with the top
open to accommodate the light guide member 1120, the light emitting
module 1110, and the reflective sheet 1130 and may be made of metal
or resin, for example.
[0163] The light emitting module 1110 may include a substrate 700
and a plurality of light emitting device package 600 mounted on the
substrate 700. The light emitting device package 600 may provide
light to the light guide member 1120. Although it is exemplified in
the embodiment that the light emitting device packages 600 are
mounted on the substrate 700 in the light emitting module 1110, the
light emitting device 100 according to an embodiment may be
directly mounted thereon.
[0164] As shown in the figures, the light emitting module 1110 may
be disposed on at least any one of the inner sides of the bottom
frame 1140, and accordingly, light can be provided to at least one
side of the light guide member 1120. However, the light emitting
module 1110 may be disposed under the bottom frame 1140 to provide
light to the bottom of the light guide member 1120, which can be
modified in various ways in accordance with design of the backlight
unit 1100 and is not limited thereto.
[0165] The light guide member 1120 may be disposed inside the
bottom frame 1140. The light guide member 1120 can convert the
light provided from the light emitting module 1110 in surface light
and guide it to a display panel (not shown).
[0166] The light guide member 1120 may be, for example, an LGP
(Light Guide Panel). The light guide panel may be made of, for
example, one of acryl resin, such as PMMA (polymethyl
metaacrylate), and PET (polyethylene terephthlate), PC (poly
carbonate), COC, and PEN (polyethylene naphthalate) resin.
[0167] An optical sheet 1150 may be disposed on the light guide
member 1120. The optical sheet 1150 may includes, for example, at
least one of a diffusion sheet, a light collecting sheet, a
luminance increasing sheet, and a fluorescent sheet. For example,
the optical sheet 1150 may be formed by stacking a diffusion sheet,
a light collecting sheet, a luminance increasing sheet, and a
fluorescent sheet. In this configuration, diffusion sheet 1150
uniformly diffuses the light radiated from light emitting module
1110 and diffused light can be collected to the display panel by
the light collecting sheet.
[0168] In this configuration, the light from the light collecting
sheet is light randomly polarized and the luminance increasing
sheet can increase degree of polarization of the light from the
light collecting sheet. The light collecting sheet may be, for
example, a horizontal or/and a vertical prism sheet. Further, the
luminance increasing sheet may be, for example, a dual brightness
enhancement film. Further, the florescent sheet may be a light
transmissive plate or film, which includes fluorescent
substances.
[0169] A reflective sheet 1130 may be disposed under the light
guide member 1120. The reflective sheet 1130 can reflect light
emitted through the bottom of the light guide member 1120, toward
the exit surface of the light guide member 1120. The reflective
sheet 1130 may be made of resin having high reflective ratio, for
example PET, PC, or PVC resin.
[0170] FIG. 23 shows one embodiment of a lighting unit 1200 that
includes a light emitting device or a light emitting device package
according to any of the aforementioned embodiments. The lighting
unit 1200 shown in FIG. 23 is an example of a lighting system.
[0171] Referring to FIG. 23, the lighting unit 1200 may include a
case body 1210, a lighting module installed to the case body 1210,
and a connecting terminal 1220 installed to the case body 1210 and
provided with power from an external power supply.
[0172] It is preferable that the case body 1210 is made of a
material having good heat dissipation properties and may be made of
metal or resin, for example.
[0173] The light emitting module 1230 may include a substrate 700
and at least one light emitting device package 600 mounted on the
substrate 700. Although it is exemplified in the embodiment that
the light emitting device packages 600 are mounted on the substrate
700 in the light emitting module 1110, the light emitting device
100 according to an embodiment may be directly mounted thereon.
[0174] The substrate 700 may be formed by printing a circuit
pattern on an insulator and may include, for example, a common PCB
(Printed Circuit Board), a metal core PCB, a flexible PCB, and a
ceramic PCB.
[0175] Further, the substrate 700 is made of a material efficiently
reflecting light, or the surface may have a color efficiently
reflecting light, such as white and silver.
[0176] At least one of the light emitting device package 600 may be
mounted on the substrate 700. The light emitting device packages
600 each may include at least one LED (Light Emitting Diode). The
light emitting diodes may include color light emitting diodes that
produce colors, such as red, green, blue, or white, and UV light
emitting diodes that produce ultraviolet rays.
[0177] The light emitting module 1230 may be disposed to have
various combinations of light emitting diodes to achieve the
impression of a color and luminance. For example, white light
emitting diodes, red light emitting diodes, and green light
emitting diodes may be combined to ensure high CRI.
[0178] Further, a fluorescent sheet may be further disposed in the
traveling path of the light emitted from the light emitting module
1230 and changes the wavelength of the light emitted from the light
emitting module 1230. For example, when the light emitted from the
light emitting module 1230 has a blue wavelength band, yellow
fluorescent substances may be included in the fluorescent sheet,
and the light emitted from the light emitting module 1230 is
finally shown as white light through the fluorescent sheet.
[0179] The connecting terminal 12220 can supply power by being
electrically connected with the light emitting module 1230.
According to the embodiment shown in FIG. 23, the connecting
terminal 1220 is turned and inserted in an external power supply,
like a socket, but is not limited thereto. For example, the
connecting terminal 1220 may be formed in a pin shape to be
inserted in an external power supply or may be connected to the
external power supply by a wire.
[0180] Since at least any one of the light guide member, a
diffusion sheet, a light collecting sheet, a luminance increasing
sheet, and a fluorescent sheet is disposed in the traveling path of
the light emitted form the light emitting module in the lighting
system as described above, it is possible to achieved desired
optical effects.
[0181] As described above, the lighting system can achieve high
light efficiency and reliability, by including light emitting
devices having reduced operational voltage and improved light
efficiency or light emitting packages.
[0182] One or more embodiments described herein provide a light
emitting device having reduced operational voltage, a light
emitting device manufacturing method, a light emitting device
package, and a lighting system. One or more of these embodiments
further provide a light emitting device having improved light
efficiency, a light emitting device manufacturing method, a light
emitting device package, and a lighting system.
[0183] A light emitting device according to an embodiment includes:
a conductive support substrate; a bonding layer on the conductive
support substrate; a reflective layer on the bonding layer; an
ohmic contact layer on the reflective layer; a current blocking
layer on the ohmic contact layer; a protection layer at a periphery
portion on the bonding layer; a light emitting structure layer on
the current blocking layer, the ohmic contact layer, and the
protection layer; and electrodes at least partially overlapping the
current blocking layer and the protection layer, on the light
emitting structure layer, in which the protection layer is made of
a material having electric conductivity lower than the reflective
layer of the ohmic contact layer, an electric insulation material,
or a material that is in schottky contact with the light emitting
structure layer.
[0184] A light emitting device according to another embodiment
includes: a conductive support substrate; a light emitting
structure layer on the conductive support substrate; a conductive
protection layer disposed at a periphery portion on the conductive
support substrate and partially disposed between the conductive
support substrate and the light emitting structure layer; and
electrodes disposed on the light emitting structure layer and at
least partially overlapping the conductive protection layer, in
which the light emitting structure layer has inclined sides, and
the inclined sides overlap the conductive protection layer.
[0185] A light emitting device according to another embodiment
includes: a conductive support substrate; a light emitting
structure layer on the conductive support substrate; a protection
layer disposed at a periphery portion on the conductive support
substrate and partially disposed between the conductive support
substrate and the light emitting structure layer; and electrodes at
least partially overlapping the protection layer on the light
emitting structure layer, in which the electrodes includes outer
electrodes, inner electrodes disposed inside the outer electrodes
and connecting the first portions and the second portions of the
outer electrodes, and pad units connected to the outer
electrodes.
[0186] According to another embodiment, a light emitting device
includes a contact layer; a blocking layer over the contact layer;
a protection layer adjacent the blocking layer; a light emitter
over the blocking layer; and an electrode layer coupled to the
light emitter. The electrode layer overlaps the blocking layer and
protection layer and wherein the blocking layer has an electrical
conductivity that substantially blocks flow of current from the
light emitter in a direction towards the contact layer.
[0187] The blocking layer includes a plurality of spaced current
blocking segments, and current flows to the light emitter through
areas between respective pairs of the current blocking segments.
The electrode layer may include a plurality of electrode segments
aligned with respective ones of the spaced current blocking
segments.
[0188] The protection layer may be made of a conductive material
and wherein current flows to the light emitter through the
protection layer, and additional current may flow to the light
emitter in an area located between the protection layer and the
blocking layer.
[0189] The blocking layer and the protection layer may be
substantially co-planar, and the blocking layer may separate a
first portion and a second portion of the protection layer. The
blocking layer may be aligned with a central region of the light
emitter, and the first and second portions of the protection layer
are aligned on either side of the central region. The protection
layer may be between a bonding layer under the light emitter.
[0190] In addition, the light emitter may have a top surface with a
predetermined pattern, the pattern substantially corresponding to
the predetermined pattern of the top surface of the light
emitter.
[0191] The width of the contact layer may be equal to or greater
than a width of the light emitter, and a reflective layer may be
provided adjacent the contact layer. A width of the reflective
layer is less than a width of the light emitter, or the width of
the reflective layer is greater than a width of the light
emitter.
[0192] The protection layer may be made of a non-conductive
material and is substantially coplanar with the blocking layer, and
wherein current flows into the light emitter through one or more
spaces between the protection layer and the blocking layer.
[0193] The blocking layer and/or protection may be made of a
material having an electrical conductivity lower than at least one
of a reflective layer to reflect light from the light emitter, the
contact layer, an electric insulation material included in the
light emitting device, or a material that is in Schottky contact
with the light emitter.
[0194] The light emitter has inclined sides and wherein the
inclined sides overlap the protection layer, and the electrode
layer may include at least two outer electrode segments; and one or
more inner electrode segments between the two outer electrode
segments, wherein the two outer electrode segments and one or more
inner electrode segments are spaced from one another.
[0195] The two outer electrode segments and the one or more inner
electrode segments are substantially equally spaced, and the two
outer electrode segments and the one or more inner electrode
segments are connected to one another to form a predetermined
pattern. The predetermined pattern includes one or more
substantially rectangular sections formed by connections between
the two outer electrode segments and the one or more inner
electrode segments. Also, one or more pad parts may be coupled to
the electrode layer.
[0196] According to another embodiment, light emitting device
package may include a package body, first and second electrode
layers coupled to the package body; and a light emitting device
according to claim 1 electrically coupled to the first and second
electrode layers.
[0197] Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
invention. The appearances of such phrases in various places in the
specification are not necessarily all referring to the same
embodiment. Further, when a particular feature, structure, or
characteristic is described in connection with any embodiment, it
is submitted that it is within the purview of one skilled in the
art to effect such feature, structure, or characteristic in
connection with other ones of the embodiments. The features of any
one embodiment may be combined with the features of any other
embodiment.
[0198] Although embodiments have been described with reference to a
number of illustrative embodiments, numerous other modifications
and embodiments can be devised by those skilled in the art that
will fall within the spirit and scope of the principles of this
disclosure. Particularly, various variations and modifications are
possible in the component parts and/or arrangements of the subject
combination arrangement within the scope of the disclosure, the
drawings and the appended claims. In addition to variations and
modifications in the component parts and/or arrangements,
alternative uses will also be apparent to those skilled in the
art.
* * * * *