U.S. patent application number 12/269499 was filed with the patent office on 2009-08-27 for semiconductor light-emitting device.
Invention is credited to Su-Hui Lin, Yi-Cun Lu, Tzong-Liang TSAI, Wei-Kai Wang.
Application Number | 20090212312 12/269499 |
Document ID | / |
Family ID | 40997432 |
Filed Date | 2009-08-27 |
United States Patent
Application |
20090212312 |
Kind Code |
A1 |
TSAI; Tzong-Liang ; et
al. |
August 27, 2009 |
SEMICONDUCTOR LIGHT-EMITTING DEVICE
Abstract
The invention discloses a semiconductor light-emitting device,
which includes a substrate, a first conductive type semiconductor
material layer, a second conductive type semiconductor material
layer, a light-emitting layer, a first electrode, a second
electrode, and a plurality of bump structures. The first conductive
type semiconductor material layer is formed on the substrate and
has an upper surface which includes a first region and a second
region distinct from the first region. The first electrode is
formed on the first region. The light-emitting layer and the second
conductive type semiconductor material layer are formed on the
second region. The bump structures are formed on the upper surface
of the first conductive type semiconductor material layer and
between the first region and the second region. Each bump structure
is made of ITO, SiO2, SiN, ZnO, polymide, BCB, SOG, InO, or
SnO.
Inventors: |
TSAI; Tzong-Liang; (Taichung
City, TW) ; Wang; Wei-Kai; (Shengang Township,
TW) ; Lin; Su-Hui; (Taichung City, TW) ; Lu;
Yi-Cun; (Taichung City, TW) |
Correspondence
Address: |
Muncy, Geissler, Olds & Lowe, PLLC
P.O. BOX 1364
FAIRFAX
VA
22038-1364
US
|
Family ID: |
40997432 |
Appl. No.: |
12/269499 |
Filed: |
November 12, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12184933 |
Aug 1, 2008 |
|
|
|
12269499 |
|
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Current U.S.
Class: |
257/98 ;
257/E33.067 |
Current CPC
Class: |
H01L 33/44 20130101;
H01L 2933/0091 20130101 |
Class at
Publication: |
257/98 ;
257/E33.067 |
International
Class: |
H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 22, 2008 |
TW |
097106193 |
Claims
1. A semiconductor light-emitting device, comprising: a substrate;
a first conductive type semiconductor material layer, the first
conductive type semiconductor material layer being formed on the
substrate and having an upper surface, and the upper surface
comprising a first region and a second region distinct from the
first region; a first electrode being formed on the first region; a
light-emitting layer being formed on the second region; a second
conductive type semiconductor material layer being formed on the
light-emitting layer; a second electrode being formed on the second
conductive type semiconductor material layer; and a plurality of
bump structures being formed on the upper surface of the first
conductive type semiconductor material layer and between the first
region and the second region, wherein each of the plurality of bump
structures is made of a material whose refractive index is larger
than 1, and the material is one selected from the group consisting
of ITO, SiO.sub.2, SiN, ZnO, polymide, BCB, SOG, InO, SnO, a Group
III-V compound semiconductor material, and a Group II-VI compound
semiconductor material.
2. The semiconductor light-emitting device of claim 1, wherein an
included angle between a part of the sidewall of each bump
structure and the upper surface of the first conductive type
semiconductor material layer is larger than or smaller than 90
degrees.
3. The semiconductor light-emitting device of claim 1, wherein the
height of a first top surface of the first electrode is
substantially equal to or smaller than that of a second top surface
of each bump structure.
4. The semiconductor light-emitting device of claim 1, wherein the
material is an insulating material.
5. The semiconductor light-emitting device of claim 1, further
comprising a transparent conductive layer, the transparent
conductive layer being formed on the upper surface of the first
conductive type semiconductor material layer and enwrapping the
second conductive type semiconductor material layer, the
light-emitting layer, and the plurality of bump structures.
6. The semiconductor light-emitting device of claim 1, wherein at
least one recess is formed on the sidewall of each bump structure
or the sidewall of each bump structure has a curved contour.
7. The semiconductor light-emitting device of claim 6, wherein the
at least one recess is further formed on the top surface of each
bump structure or the top surface of each bump structure further
has a curved contour.
8. The semiconductor light-emitting device of claim 1, wherein the
first conductive type is N type, and the second conductive type is
P type.
9. The semiconductor light-emitting device of claim 1, wherein the
substrate is formed by one selected from the group consisting of
glass, silicon, GaN, GaAs, GaP, AlN, sapphire, spinel,
Al.sub.2O.sub.3, SiC, ZnO, MgO, LiAlO.sub.2, LiGaO.sub.2 and
MgAlO.sub.4.
10. The semiconductor light-emitting device of claim 1, further
comprising a transparent conductive layer, the transparent
conductive layer being formed on the second conductive type
semiconductor material layer.
11. A semiconductor light-emitting device, comprising: a substrate;
a first conductive type material semiconductor layer, the first
conductive type semiconductor material layer being formed on the
substrate and having an upper surface, and the upper surface
comprising a first region and a second region distinct from the
first region; a first electrode being formed on the first region; a
light-emitting layer being formed on the second region; a second
conductive type semiconductor material layer being formed on the
light-emitting layer; a second electrode being formed on the second
conductive type semiconductor material layer; and a plurality of
bump structures being formed on the upper surface of the first
conductive type semiconductor material layer and between the first
region and second region, wherein each of the bump structures is
formed by a first structure layer and a second structure layer, the
first structure layer is formed on the upper surface of the first
conductive type semiconductor material layer, the second structure
layer is formed on the first structure layer and is made of a
material whose refractive index is larger than 1, and the material
is one selected from the group consisting of ITO, SiO.sub.2, SiN,
ZnO, polymide, BCB, SOG, InO, SnO, a Group III-V compound
semiconductor material, and a Group II-VI compound semiconductor
material.
12. The semiconductor light-emitting device of claim 11, wherein
the height of a first top surface of the first electrode is
substantially equal to or smaller than that of a second top surface
of each bump structure.
13. The semiconductor light-emitting device of claim 12, wherein
the height of a third top surface of the first structure layer is
substantially equal to or smaller than that of a fourth top surface
of the second conductive type semiconductor material layer.
14. The semiconductor light-emitting device of claim 11, wherein an
included angle between a part of the sidewall of each bump
structure and the upper surface of the first conductive type
semiconductor material layer is larger than or smaller than 90
degrees.
15. The semiconductor light-emitting device of claim 11, further
comprising a transparent conductive layer, the transparent
conductive layer being formed on the upper surface of the first
conductive type semiconductor material layer and enwrapping the
second conductive type semiconductor material layer, the
light-emitting layer, and the plurality of bump structures.
16. The semiconductor light-emitting device of claim 11, wherein at
least one recess is further formed on the sidewall of each bump
structure or the sidewall of each bump structure has a curved
contour.
17. The semiconductor light-emitting device of claim 16 wherein the
at least one recess is further formed on the top surface of each
bump structure or the top surface of each bump structure further
has a curved contour.
18. The semiconductor light-emitting device of claim 11, wherein
the first conductive type is N type, and the second conductive type
is P type.
19. The semiconductor light-emitting device of claim 11, wherein
the substrate is formed by one selected from the group consisting
of glass, silicon, GaN, GaAs, GaP, AlN, sapphire, spinel,
Al.sub.2O.sub.3, SiC, ZnO, MgO, LiAlO.sub.2, LiGaO.sub.2 and
MgAlO.sub.4.
20. The semiconductor light-emitting device of claim 11, further
comprising a transparent conductive layer, the transparent
conductive layer being formed on the second conductive type
semiconductor material layer.
21. A semiconductor light-emitting device, comprising: a substrate
having a first upper surface; a plurality of bump structures being
formed on the first upper surface of the substrate, wherein each of
the plurality of bump structures is made of a material whose
refractive index is larger than 1; a first conductive type
semiconductor material layer, the first conductive type
semiconductor material layer covering the first upper surface of
the substrate, so as to make the plurality of bump structures to
expose out of the first conductive type semiconductor material
layer, wherein the first conductive type semiconductor material
layer has a second upper surface, and the second upper surface
comprises a first region and a second region distinct from the
first region; a light-emitting layer being formed on the second
region; a first electrode being formed on the first region, so that
the plurality of bump structures are between the light-emitting
layer and the first electrode; a second conductive type
semiconductor material layer being formed on the light-emitting
layer; and a second electrode being formed on the second conductive
type semiconductor material layer.
22. The semiconductor light-emitting device of claim 21, wherein
the material is one selected from the group consisting of ITO,
SiO.sub.2, SiN, ZnO, polymide, BCB, SOG, InO, SnO, a Group III-V
compound semiconductor material, and a Group II-VI compound
semiconductor material.
23. The semiconductor light-emitting device of claim 21, further
comprising a transparent conductive layer, the transparent
conductive layer being formed on the second conductive type
semiconductor material layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of co-pending application
Ser. No. 12/184,933, filed on Aug. 1, 2008, and for which priority
is claimed under 35 U.S.C. .sctn. 120; the entire contents of which
are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a semiconductor light-emitting
device and, more particularly, to a semiconductor light-emitting
device which has high light-extraction efficiency.
[0004] 2. Description of the Prior Art
[0005] In general, semiconductor light-emitting devices (e.g.,
light-emitting diodes) have been widely used in many application
fields, such as key switch systems, back light modules of cell
phones, vehicle lighting systems, decorative illuminations, and
remote-controlled devices. In order to ensure higher functional
reliability and lower energy consumption of semiconductor
light-emitting devices, the external quantum efficiency of the
semiconductor light-emitting device needs to be well dominated.
[0006] In theory, the external quantum efficiency of the
semiconductor light-emitting device relates to its internal quantum
efficiency and its light-extraction efficiency. And, the external
quantum efficiency is determined by properties and quality of
material; the light-extraction efficiency refers to the radiation
ratio of the radiation emitted from the internal part of device to
air or to the encapsulation material (i.e. epoxy resin). Moreover,
the light-extraction efficiency is determined by the consumption
that is generated while the irradiation is emitted out of the
device. One of the reasons of the consumption is that the
semiconductor material of the surface layer formed on the device
has high refraction coefficient, which forms total reflection on
the surface of the material and then makes light unable to be
emitted outward. Accordingly, if the light-extraction efficiency
rises, the external quantum efficiency of the semiconductor
light-emitting device raise as well.
[0007] Please refer to FIG. 1. FIG. 1 is a schematic diagram
illustrating a light-emitting diode 1 of prior arts. As shown in
FIG. 1, the light-emitting diode 1 comprises a substrate 10, N-type
GaN 12, P-type GaN 16, a light-emitting region 14 and electrodes
18. In order to electrically connect the P-type GaN 16 and the
N-type GaN 12 to operate the light-emitting diode 1, one of the
electrodes 18 is formed on the P-type GaN 16 and another electrode
18 is formed on the N-type GaN 12. Before forming the another
electrode 18, the light-emitting diode 1 needs to partially etch
the P-type GaN 16, the light-emitting region 14, and the N-type GaN
12 by etching processes. Then, another electrode 18 is formed on
the exposure part of the N-type GaN 12. However, because the
light-emitting region 14 is partially etched, not only the emitting
area of the light-emitting diode 1 reduces, but also the
light-emitting efficiency decreases, as shown in FIG. 1.
[0008] Although various kinds of light-emitting diodes are
disclosed nowadays, how to increase the light-extraction efficiency
of light-emitting diodes and how to enable the light-emitting diode
to emit wide and uniform light are always popular. Accordingly, the
scope of the invention is to provide a semiconductor light-emitting
device to solve the above-mentioned problems.
SUMMARY OF THE INVENTION
[0009] A scope of the invention is to provide a semiconductor
light-emitting device. The semiconductor light-emitting device has
high light-extraction efficiency and is capable of emitting a wide
and uniform light.
[0010] According to an embodiment of the invention, the
semiconductor light-emitting device includes a substrate, a first
conductive type semiconductor material layer, a second conductive
type semiconductor material layer, a light-emitting layer, a first
electrode, a second electrode, and a plurality of bump
structures.
[0011] The first conductive type semiconductor material layer is
formed on the substrate. The first conductive type semiconductor
material layer has an upper surface, and the upper surface includes
a first region and a second region which is distinct from the first
region. The first electrode is formed on the first region, and the
light-emitting layer is formed on the second region. The second
conductive type semiconductor material layer is formed on the
light-emitting layer. The second electrode is formed on the second
conductive type semiconductor material layer. The plurality of bump
structures are formed on the upper surface of the first conductive
type semiconductor material layer and between the first region and
the second region
[0012] Furthermore, each of the plurality of bump structures is
made of the material whose refraction index is larger than one, and
the material refers to ITO, SiO.sub.2, SiN, ZnO, polymide, BCB,
SOG, InO, or SnO.
[0013] According to another embodiment of the invention, each of
the plurality of bump structures is formed by a first structure
layer and a second structure layer. The first structure layer is
formed on the upper surface of the first conductive type
semiconductor material layer. The second structure layer is formed
on the first structure layer and is made of the material whose
refraction index is larger than 1. The material refers to ITO,
SiO.sub.2, SiN, ZnO, polymide, BCB, SOG, InO, or SnO.
[0014] The advantage and spirit of the invention may be understood
by the following recitations together with the appended
drawings.
BRIEF DESCRIPTION OF THE APPENDED DRAWINGS
[0015] FIG. 1 is a schematic diagram illustrating a light-emitting
diode of prior arts.
[0016] FIG. 2A is a cross-sectional view illustrating a
semiconductor light-emitting device according to an embodiment of
the invention.
[0017] FIG. 2B is a cross-sectional view illustrating another
semiconductor light-emitting device according to an embodiment of
the invention.
[0018] FIG. 3 is a schematic diagram illustrating that the sidewall
of each bump structure has a curved contour.
[0019] FIG. 4 is a top view illustrating the semiconductor
light-emitting device according to the invention.
[0020] FIG. 5A is a cross-sectional view illustrating at least one
recess which is further formed on the top surface of the bump
structure in FIG. 2A.
[0021] FIG. 5B is a cross-sectional view illustrating at least one
recess which is further formed on the top surface of the bump
structure in FIG. 2B.
[0022] FIG. 6 is a cross-sectional view illustrating the
semiconductor light-emitting device which further includes a
transparent conductive layer according to an embodiment of the
invention.
[0023] FIG. 7 is a cross-sectional view illustrating a
semiconductor light-emitting device 4 according to another
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Please refer to FIG. 2A. FIG. 2A is a cross-sectional view
illustrating a semiconductor light-emitting device 2 according to
an embodiment of the invention.
[0025] As shown in FIG. 2A, the semiconductor light-emitting device
2 includes a substrate 20, a first conductive type semiconductor
material layer 22, a light-emitting layer 24, a second conductive
type semiconductor material layer 26, a first electrode 30, a
second electrode 32, and a plurality of bump structures 28.
[0026] In a practical application, the substrate 20 can be, but not
limited to, glass, silicon, Ge, GaN, GaAs, GaP, AlN, sapphire,
spinnel, Al.sub.2O.sub.3, SiC, ZnO, MgO, LiAlO.sub.2, GaLiO.sub.2,
or MgAlO.sub.4.
[0027] According to an embodiment, the first conductive type
semiconductor material layer 22 and the second conductive type
semiconductor material layer 26 are made of Group III-V compound
semiconductor material.
[0028] The Group III element of the Group III-V compound
semiconductor material can be such as Al, Ga, or In. The Group V
element of the Group III-V compound semiconductor material can be
N, P, or As. In the embodiment, the first conductive type
semiconductor material layer 22 and the second conductive type
semiconductor material layer 26 can be made of GaN.
[0029] The first conductive type semiconductor material layer 22 is
formed on the substrate 20, and the first conductive type can be N
type. In other words, the first conductive type semiconductor
material layer 22 is a N type GaN contact layer. The first
conductive type semiconductor material layer 22 has an upper
surface 220, and the upper surface 220 includes a first region 2200
and a second region 2202 which is distinct from the first region
2200. The first electrode 30 is formed on the first region 2200,
and the light-emitting layer 24 is formed on the second region
2202. The first electrode 30 is a N type electrode.
[0030] The second conductive type semiconductor material layer 26
is formed on the light-emitting layer 24. The second conductive
semiconductor material layer 26 which corresponds to the first
conductive semiconductor material layer 22 is a P type GaN contact
layer. The second electrode 32 can be formed on the second
conductive type semiconductor material layer 26, and the second
electrode is a P type electrode. Moreover, a transparent conductive
layer (not shown in the figures) can be further formed on the
second conductive type semiconductor material layer 26.
[0031] As shown in FIG. 2A, the plurality of bump structures 28 are
formed on the upper surface 220 of the first conductive type
semiconductor material layer 22 and between the first region 2200
and the second region 2202. In a practical application, each bump
structure 28 can be in a form of a column, an ellipse, or a
polygon, etc., according to the top view.
[0032] According to the invention, each bump structure 28 can be
made of a specific material whose refraction index is larger than
1. The specific material can be, but not limited to, ITO,
SiO.sub.2, SiN, ZnO, polymide, BCB, SOG, InO, SnO, a Group III-V
compound semiconductor material, or a Group II-VI compound
semiconductor material. The Group III element and the Group V
element of the Group III-V compound semiconductor material are the
same as the above-mentioned description. The Group II element of
the Group II-VI compound semiconductor material can be Be, Mg, Ga,
or Sr. The Group VI element of the Group II-VI compound
semiconductor material can be O, S, Se, or Te. In an embodiment,
each bump structure 28 also can be formed by the insulation
material whose refraction index is larger than 1.
[0033] Owing to the difference between the refraction index of air
and that of the specific material, the light-extraction efficiency
of the semiconductor light-emitting device 2 can be effectively
prompted. Because the refraction index of the specific material is
larger than 1 (e.g., the refraction index of air is 1), the side
light emitted by the semiconductor light-emitting device 2 can be
refracted upward or downward via the specific material and prevent
from being absorbed by the first electrode 30 to increase the
light-extraction efficiency of the semiconductor light-emitting
device 2.
[0034] In order to prevent the light which is emitted from the
light-emitting layer 24 from being absorbed by the first electrode
30, the height of each bump structure 28 can be substantially equal
to or higher than that of the first electrode 30. As shown in FIG.
2A, if the upper surface 220 of the first conductive type
semiconductor material layer 22 is regarded as a reference plane,
the height of the top surface 300 of each first electrode 30 is D1,
the height of the top surface 280 of each bump surface 28 is D2,
and D2 can be substantially equal to or larger than D1 to prevent
the light from emitting to the first electrode 30.
[0035] Please refer to the FIG. 2B. FIG. 2B is schematic diagram
illustrating a cross-sectional view of the semiconductor
light-emitting device 2 according to another embodiment of the
invention. In the embodiment, each bump structure 28 can comprise a
first structure layer 282 and a second structure layer 284. In a
practical application, the first structure layer 282 can be
composed of the first conductive type semiconductor material layer
22, the second conductive type semiconductor material layer 26 and
the light-emitting layer 24. It is notable that in order to prevent
the light which is emitted form the semiconductor light-emitting
device 2 from being absorbed, the light-emitting layer 284 of each
bump structure 28 can be removed. Or, the first structure layer 282
can be totally composed of the first conductive type semiconductor
material layer 22. The second structure layer 284 is formed on the
first structure 282 and is made of a specific material whose
refraction index is larger than 1. And, the specific material can
be, but not limited to, ITO, SiO.sub.2, ZnO, polymide, BCB, SOG,
InO or SnO.
[0036] In one preferred embodiment, it is assumed that the upper
surface 220 of the first conductive type semiconductor material
layer 22 is regarded as a reference plane. Then, the height of the
top surface 300 of first electrode 30 is D1, the height of the top
surface 280 of each bump structure 28 is D2, and D2 is
substantially equal to or larger than D1 to prevent the light which
is emitted by the light-emitting layer 24 from being absorbed by
the first electrode 30. Thus, the light which is emitted by the
light-emitting layer 24 can prevent from being absorbed by the
first electrode 30 to increase the light-extraction efficiency;
moreover, the height of the top surface 2820 of the first structure
layer 282 will be D3, and the height of the top surface 260 of the
second conductive type semiconductor material layer 26 will be D4,
wherein, D4 is substantially equal to or larger than D3.
[0037] Please refer to the FIG. 2A and FIG. 2B. In an embodiment,
at least one recess 2800 is formed in the sidewall of each bump
structure 28. As shown in the FIG. 2A and FIG. 2B, the sidewall of
each bump structure 28 is incised, so that the sidewall forms a
plurality of recess 2800. That is to say, the sidewall of each bump
structure 28 has a roughened surface morphology. Or in another
embodiment, the sidewall of each bump structure 28 substantially
has a curved contour, as shown in FIG. 3.
[0038] Assume that the sidewall of each bump structure 28 has a
straight contour, and the included angle between the sidewall and
the upper surface 220 of the first conductive type semiconductor
material layer 22 equals to 90 degrees, the light which is emitted
from the light-emitting layer 24 will be constrained to be
reflected between the bump structure 28 and the main body of the
semiconductor light-emitting device 2. However, because each
sidewall of the bump structure 28 has a roughened surface
morphology or a curved contour, the included angle .theta. between
a part of the sidewall and the upper surface 220 of the first
conductive type semiconductor material layer 22 may be larger than
or smaller than 90 degrees, as shown in FIG. 2A, FIG. 2B, and FIG.
3. Thus, the light which is emitted from the light-emitting layer
24, especially the side light, can be reflected to change the
direction by the sidewall of the bump structure 28 after being
emitted to the bump structure 28. And, the probability of emitting
the light out of the observation side of the semiconductor
light-emitting device 2 thus increases.
[0039] In additional, assume that the observation side of the
semiconductor light-emitting device 2 is upward, the light which is
emitted from the light-emitting layer toward the bottom of the
semiconductor light-emitting device 2 will be guided to emit out
the observation side by the plurality of bump structures 28 when
the light is reflected to be emitted toward the plurality of bump
structures 28. Besides, if the plurality of bump structures 28 is
distributed uniformly on the upper surface 220 of the first
conductive semiconductor material layer 22, the semiconductor
light-emitting device 2 can produce the light that is wider and
more uniform.
[0040] Please refer to FIG. 4. FIG. 4 is a top view illustrating
the semiconductor light-emitting device 2 according to the
invention. In a practical application, the plurality of bump
structures 28 need to be surrounded by the light-emitting layer 24
(not shown in FIG. 4) to guide the light emitted from the
light-emitting layer 24 toward the observation side of the
semiconductor light-emitting device 2. In a preferred embodiment,
the plurality of bump structures 28 can be arranged to be two
substantially concentric circular patterns, and the circular
patterns are staggered to ensure that the plurality of bump
structures 28 guide the light emitted from the light-emitting layer
24 toward the observation side of the semiconductor light-emitting
device 2, as the FIG. 4 shown. Furthermore, the plurality of bump
structures 28 also can be fully disposed on the upper surface 220
of the first conductive type semiconductor material layer 22 to
ensure that the light-extraction efficiency of the semiconductor
light-emitting device 2 can be increased.
[0041] Please refer to the FIG. 5A and FIG. 5B. FIG. 5A is a
cross-sectional view illustrating at least one recess 2802 which is
further formed on the top surface 280 of the bump structure 28 in
FIG. 2A. FIG. 5B is a cross-sectional view illustrating at least
one recess 2802 which is further formed on the top surface 280 of
the bump structure 28 in FIG. 2B. In other words, the top surface
280 of the bump structure 28 can also has a roughened surface
morphology besides the sidewall. In a practical application, the
top surface 280 of the bump structure 28 can also has a curved
contour. And, whatever the top surface 280 of the bump structure 28
has a roughened surface morphology or a curved contour, and it can
increase the light-extraction efficiency.
[0042] Please refer to FIG. 6. FIG. 6 is a cross-sectional view
illustrating the semiconductor light-emitting device 2 which
further includes a transparent conductive layer 34 according to one
embodiment of the invention. As shown in FIG. 6, the transparent
conductive layer 34 is formed on the upper surface 220 of the first
conductive type semiconductor material layer 22 and enwraps the
second conductive type semiconductor material layer 26, the
light-emitting layer 24, and the plurality of bump structures 28.
In the embodiment, the second electrode 32 can be formed on the
transparent conductive layer 34 after the transparent conductive
layer 34 is formed. In a practical application, the transparent
conductive layer 34 can be made of, but not limited to, a thin
metal layer, a meshed conductive layer, ITO, or ZnO.
[0043] Please refer to FIG. 7. FIG. 7 is a cross-sectional view
illustrating a semiconductor light-emitting device 4 according to
another embodiment of the invention. As shown in FIG. 7, the
semiconductor light-emitting device 4 includes a substrate 40, a
plurality of bump structures 48, a first conductive type
semiconductor material layer 42, a light-emitting layer 44, a
second conductive type semiconductor material layer 46, a first
electrode 50, and a second electrode 52. The substrate 40 has a
first upper surface 400. The plurality of bump structures 48 are
formed on the first upper surface 400 of the substrate 40. Each of
the plurality of bump structures 48 is made of a material whose
refractive index is larger than 1. The first conductive type
semiconductor material layer 42 covers the first upper surface 400
of the substrate 40, so as to make the plurality of bump structures
48 to expose out of the first conductive type semiconductor
material layer 42. The first conductive type semiconductor material
layer 42 has a second upper surface 420, and the second upper
surface 420 comprises a first region 4200 and a second region 4202
distinct from the first region 4200. The light-emitting layer 44 is
formed on the second region 4202. The first electrode 50 is formed
on the first region 4200, so that the plurality of bump structures
48 are between the light-emitting layer 44 and the first electrode
50. The second conductive type semiconductor material layer 46 is
formed on the light-emitting layer 44. The second electrode 52 is
formed on the second conductive type semiconductor material layer
46.
[0044] Compared with prior arts, the semiconductor light-emitting
device according to the invention can guide the light emitted from
the semiconductor light-emitting device toward the observation side
by the plurality of bump structures, so as to increase the
light-extraction efficiency of the semiconductor light-emitting
device and generate the light that is wider and more uniform.
Particularly, the bump structure according to the invention can has
a roughened surface morphology or a curved contour, thus the
light-extraction efficiency can be prompted. Additionally, owing to
high light-extraction efficiency, the semiconductor light-emitting
device of the invention can be applied to photo-pump.
[0045] With the example and explanations above, the features and
spirits of the invention will be hopefully well described. Those
skilled in the art will readily observe that numerous modifications
and alterations of the device may be made while retaining the
teaching of the invention. Accordingly, the above disclosure should
be construed as limited only by the metes and bounds of the
appended claims.
* * * * *