U.S. patent application number 15/711737 was filed with the patent office on 2018-01-11 for light-emitting device and manufacturing method thereof.
The applicant listed for this patent is Epistar Corporation. Invention is credited to Yi-Ming CHEN, Tzu-Chieh HSU, Chun-Yu LIN, Shao-Ping LU, Yu-Ren PENG, Chun-Fu TSAI.
Application Number | 20180012929 15/711737 |
Document ID | / |
Family ID | 57836230 |
Filed Date | 2018-01-11 |
United States Patent
Application |
20180012929 |
Kind Code |
A1 |
LU; Shao-Ping ; et
al. |
January 11, 2018 |
LIGHT-EMITTING DEVICE AND MANUFACTURING METHOD THEREOF
Abstract
A light-emitting device comprises a carrier; a first
semiconductor element formed on the carrier and comprising a first
semiconductor structure and a second semiconductor structure,
wherein the second semiconductor structure is closer to the carrier
than the first semiconductor structure is, the first semiconductor
structure comprises a first active layer emitting a first light
having a first dominant wavelength during a normal operation, and
the second semiconductor structure comprises a second active layer;
and a bridge on a side surface of the second active layer of the
second semiconductor structure.
Inventors: |
LU; Shao-Ping; (Hsinchu,
TW) ; CHEN; Yi-Ming; (Hsinchu, TW) ; PENG;
Yu-Ren; (Hsinchu, TW) ; LIN; Chun-Yu;
(Hsinchu, TW) ; TSAI; Chun-Fu; (Hsinchu, TW)
; HSU; Tzu-Chieh; (Hsinchu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Epistar Corporation |
Hsinchu |
|
TW |
|
|
Family ID: |
57836230 |
Appl. No.: |
15/711737 |
Filed: |
September 21, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14808295 |
Jul 24, 2015 |
9825088 |
|
|
15711737 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 33/08 20130101;
H01L 33/005 20130101; H01L 27/153 20130101 |
International
Class: |
H01L 27/15 20060101
H01L027/15 |
Claims
1. A light-emitting device, comprising: a carrier; a first
semiconductor element formed on the carrier and comprising a first
semiconductor structure and a second semiconductor structure,
wherein the second semiconductor structure is closer to the carrier
than the first semiconductor structure is, the first semiconductor
structure comprises a first active layer emitting a first light
having a first dominant wavelength during a normal operation, and
the second semiconductor structure comprises a second active layer;
and a bridge on a side surface of the second active layer of the
second semiconductor structure.
2. The light-emitting device of claim 1, further comprising a
tunnel junction between the first semiconductor structure and the
second semiconductor structure, wherein the tunnel junction
comprises a p-n junction.
3. The light-emitting device of claim 2, wherein the tunnel
junction comprises a first layer of a first conductivity-type and a
second layer of a second conductivity-type, and the first
conductivity-type is different from the second
conductivity-type.
4. The light-emitting device of claim 3, wherein the first
semiconductor element comprises a semiconductor layer on the first
active layer and having a doping concentration, and the first layer
of the first conductivity-type and/or the second layer of the
second conductivity-type has a doping concentration at least one
order higher than the doping concentration of the semiconductor
layer of the first semiconductor element.
5. The light-emitting device of claim 1, wherein the carrier
comprises a side face, the first semiconductor structure comprises
a side face, and the side surface of the second active layer is
between the side face of the first semiconductor structure and the
side face of the carrier.
6. The light-emitting device of claim 1, further comprising a
second semiconductor element on the carrier, wherein the first
semiconductor element is physically spaced apart from the second
semiconductor element.
7. The light-emitting device of claim 6, wherein the second
semiconductor element comprises a third semiconductor structure
emitting a second dominant wavelength during a normal
operation.
8. The light-emitting device of claim 7, wherein the first dominant
wavelength is different from the second dominant wavelength.
9. The light-emitting device of claim 1, wherein the second
semiconductor structure comprises a top surface, and the
light-emitting device further comprises a contact on the top
surface of the second semiconductor structure.
10. The light-emitting device of claim 9, wherein the bridge is in
contact with the contact.
11. The light-emitting device of claim 9, wherein the second
semiconductor structure comprises a third semiconductor layer, a
fourth semiconductor layer, and the second active layer is between
the third semiconductor layer and the fourth semiconductor layer;
and wherein the bridge extends from the contact, and covers a side
surface of the third semiconductor layer and a side surface of the
fourth semiconductor layer.
12. The light-emitting device of claim 1, wherein the second
semiconductor structure comprises a third semiconductor layer, a
fourth semiconductor layer, and the second active layer is between
the third semiconductor layer and the fourth semiconductor layer;
and wherein the bridge covers a side surface of the third
semiconductor layer and a side surface of the fourth semiconductor
layer.
13. The light-emitting device of claim 1, further comprising a
first top electrode and a bottom electrode, wherein the first top
electrode is on the first semiconductor structure, and the bottom
electrode is on a side of the carrier opposite to the first
semiconductor structure.
14. The light-emitting device of claim 13, further comprising a
second semiconductor element on the carrier, wherein the first
semiconductor element is physically spaced apart from the second
semiconductor element, and the second semiconductor element
comprises a third semiconductor structure.
15. The light-emitting device of claim 14, further comprising a
second top electrode on the third semiconductor structure.
16. The light-emitting device of claim 15, wherein the bottom
electrode is vertically overlapped with the first top electrode,
the second top electrode and the bridge.
17. The light-emitting device of claim 15, wherein the second top
electrode is closer to the carrier than the first top electrode
is.
18. The light-emitting device of claim 1, further comprising an
etching stop layer formed between the first semiconductor structure
and the second semiconductor structure.
19. The light-emitting device of claim 1, wherein the second active
layer does not emit light during the normal operation.
20. The light-emitting device of claim 1, further comprising an
adhesive layer between the second semiconductor structure and the
carrier.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of a
previously filed U.S. patent application Ser. No. 14/808,295 filed
on Jul. 24, 2015, entitled as "LIGHT-EMITTING DEVICE AND
MANUFACTURING METHOD THEREOF". The disclosure of the reference
cited herein is incorporated by reference.
TECHNICAL FIELD
[0002] The disclosure relates to a light-emitting device, and more
particularly, to a light-emitting device emitting multiple dominant
wavelengths.
DESCRIPTION OF BACKGROUND ART
[0003] Light-emitting diode (LED) is widely used as a solid-state
lighting source. Light-emitting diode (LED) generally comprises a
p-type semiconductor layer, an n-type semiconductor layer, and an
active layer between the p-type semiconductor layer and the n-type
semiconductor layer for emitting light. The principle of LED is to
transform electrical energy to optical energy by applying
electrical current to LED and injecting electrons and holes to the
active layer. The combination of electrons and holes in the active
layer emits light accordingly.
SUMMARY OF THE DISCLOSURE
[0004] A light-emitting device comprises a carrier; a first
semiconductor element formed on the carrier and comprising a first
semiconductor structure and a second semiconductor structure,
wherein the second semiconductor structure is closer to the carrier
than the first semiconductor structure is, the first semiconductor
structure comprises a first active layer emitting a first light
having a first dominant wavelength during a normal operation, and
the second semiconductor structure comprises a second active layer;
and a bridge on a side surface of the second active layer of the
second semiconductor structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIGS. 1A-1D show a process flow of a manufacturing method of
a light-emitting device in accordance with an embodiment of the
present disclosure;
[0006] FIG. 2 shows a sectional view of a light-emitting device in
accordance with a first embodiment of the present disclosure;
and
[0007] FIG. 3 shows a sectional view of a light-emitting device in
accordance with a second embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE
[0008] FIGS. 1A-1D show a process flow of a method of manufacturing
a light-emitting device 1 in accordance with an embodiment of the
present disclosure. As shown in FIG. 1A, the method of
manufacturing the light-emitting device 1 comprises a step of
epitaxially grown a first semiconductor stack 11 on a growth
substrate 10 by epitaxy method, such as metallic-organic chemical
vapor deposition (MOCVD) method, molecular beam epitaxy (MBE)
method, or hydride vapor phase epitaxy (HVPE) method. The growth
substrate 10 comprises a single-crystal material having a
single-crystal plane on which the first semiconductor stack 11 can
be epitaxially grown, wherein the single-crystal plane comprises
sapphire C-plane, sapphire R-plane, or sapphire A-plane. In another
example, the growth substrate 10 comprises metal oxide or a
semiconductor material such as silicon carbide (SiC), silicon, ZnO,
GaAs, or GaN. The first semiconductor stack 11 comprises a first
semiconductor layer 111 having a first conductivity-type, a second
semiconductor layer 113 having a second conductivity-type different
from the first conductivity-type, and a first active layer 112
formed between the first semiconductor layer 111 and the second
semiconductor layer 113. The first active layer 112 comprises a
single heterostructure (SH), a double heterostructure (DH), or a
multi-quantum well (MQW) structure. In one embodiment, the first
semiconductor layer 111 is an n-type semiconductor layer for
providing electrons, the second semiconductor layer 113 is a p-type
semiconductor layer for providing holes, and holes and electrons
combine in the first active layer 112 to emit light under a driving
current. Alternatively, the first semiconductor layer 111 can be a
p-type semiconductor layer, and the second semiconductor layer 113
can be an n-type semiconductor layer. The material of the first
active layer 112 comprises In.sub.xGa.sub.yAl.sub.(1-x-y)N for
emitting light having a dominant wavelength in the ultraviolet to
green spectral regions, In.sub.xGa.sub.yAl.sub.(1-x-y)P for
emitting light having a dominant wavelength in the yellow to red
spectral regions, or In.sub.xGa.sub.yAl.sub.(1-x-y)As for emitting
light having a dominant wavelength in the infrared spectral
region.
[0009] Next, the method comprises a step of epitaxially growing a
reflective layer 13 on the first semiconductor stack 11. The
reflective layer 13 comprises a DBR structure and group III-V
semiconductor material. The reflective layer 13 comprises a
conductivity-type same as that of the second semiconductor layer
113 of the first semiconductor stack 11. Next, a tunnel junction 14
comprising group III-V semiconductor material is epitaxially grown
on the first semiconductor stack 11. The tunnel junction 14
comprises a p-n junction formed by a first heavily-doped layer of a
first conductivity-type, for example an n-type conductive
semiconductor layer, and a second heavily-doped layer of a second
conductivity-type, for example a p-type semiconductor layer. The
heavily-doped n-type conductive semiconductor layer and the
heavily-doped p-type layer have a doping concentration at least one
order higher than that of the semiconductor layer of the first
semiconductor stack 11. These heavily-doped layers of the tunnel
junction 14 are preferable doped with a doping concentration
greater than 10.sup.18/cm.sup.3, thus providing a low electrical
junction resistance during operation. The tunnel junction 14 having
low resistance is provided to be an electrical junction between the
first semiconductor structure 11a and another semiconductor
structure deposited thereon in the following process. A side of the
tunnel junction 14, which is adjacent to the second semiconductor
layer 113 or the reflective layer 13, comprises a conductivity-type
same as that of the second semiconductor layer 113 or the
reflective layer 13. An opposite side of the tunnel junction 14,
which is away from the second semiconductor layer 113 or the
reflective layer 13, comprises a conductivity-type opposite to that
of the second semiconductor layer 113 or the reflective layer
13.
[0010] Then, an etching stop layer 23 is epitaxially grown on the
first semiconductor stack 11. Next, a second semiconductor stack 15
is epitaxially grown on the etching stop layer 23 by epitaxy
method, such as metallic-organic chemical vapor deposition (MOCVD)
method, molecular beam epitaxy (MBE) method, or hydride vapor phase
epitaxy (HVPE) method. The second semiconductor stack 15 comprises
a third semiconductor layer 151 having a first conductivity-type, a
fourth semiconductor layer 153 having a second-conductivity type
different from the first conductivity-type, and an second active
layer 152 formed between the third semiconductor layer 151 and the
fourth semiconductor layer 153. The second active layer 152
comprises a single heterostructure (SH), a double heterostructure
(DH), or a multi-quantum well (MQW) structure. In one embodiment,
the third semiconductor layer 151 is an n-type semiconductor layer
for providing electrons, the fourth semiconductor layer 153 is a
p-type semiconductor layer for providing holes, and holes and
electrons combine in the second active layer 152 to emit light
under a driving current. Alternatively, the third semiconductor
layer 151 can be a p-type semiconductor layer, and the fourth
semiconductor layer 153 can be an n-type semiconductor layer. The
material of the second active layer 152 comprises
In.sub.xGa.sub.yAl.sub.(1-x-y)N for emitting light having a
dominant wavelength in the ultraviolet to green spectral regions,
In.sub.xGa.sub.yAl.sub.(1-x-y)P for emitting light having a
dominant wavelength in the yellow to red spectral regions, or
In.sub.xGa.sub.yAl.sub.(1-x-y)As for emitting light having a
dominant wavelength in the infrared spectral region.
[0011] The first semiconductor stack 11, the reflective layer 13,
the tunnel junction 14, the etching stop layer 23, and the second
semiconductor stack 15 are deposited on the growth substrate
continuously in an epitaxy chamber to prevent from being
contaminated and to ensure a high quality of the semiconductor
layers that staked.
[0012] As shown in FIG. 1B, the method of manufacturing the
light-emitting device 1 further comprises a bonding step of flipped
mounting the multi-layered structure formed by the above steps to a
carrier 20 by bonding the fourth semiconductor layer 153 of the
second semiconductor stack 15 to the carrier 20 through an adhesive
layer 21 and a thermally pressing process, wherein the carrier 20
comprises a first region and a second region next to the first
region. The bonding layer is made of an adhesive material. A
material of the carrier 20 and the adhesive layer 21 comprises
conductive material, such as metal or solder. In a variant of the
embodiment, the carrier 20 comprises a thermal conductive material
or an insulated material. Next, the growth substrate 10 is removed
after the fourth semiconductor layer 153 of the second
semiconductor stack 15 is bonded to the carrier 20.
[0013] As shown in FIG. 1C, the method of manufacturing the
light-emitting device 1 further comprises forming a patterned mask
(not shown) on the first semiconductor stack 11 by a
photolithographic process and etching the first semiconductor stack
11 over the second region of the carrier, such as a portion of the
first semiconductor stack 11, the reflective layer 13, and the
tunnel junction 14 not covered by the patterned mask by chemical
wet etching or dry etching to expose the etching stop layer 23
while retaining the first semiconductor stack 11 over the first
region of the carrier 20. The etching stop layer 23 is formed of a
group III-V material, such as InGaP, having a relative lower
etching rate than the first semiconductor stack 11 in the etching
step. The portion of the first semiconductor stack 11 covered by
the patterned mask is remained on the second semiconductor stack 15
to form a first semiconductor structure 11a.
[0014] As shown in FIG. 1D, the method of manufacturing the
light-emitting device 1 further comprises forming a groove 30
through the exposed etching stop layer 23 and the second
semiconductor stack 15. The groove 30 divides the second
semiconductor stack 15 into a second semiconductor structure 15a
and a third semiconductor structure 15b, wherein the second
semiconductor structure 15a is formed between the carrier 20 and
the first semiconductor structure 11a, and the third semiconductor
structure 15b is formed above the carrier 20 and spaced apart from
the second semiconductor structure 15a.
[0015] Next, as shown in FIG. 2 or FIG. 3, a bottom electrode 22 is
arranged on rear side of the carrier 20 to be electrically
connected both to the first semiconductor structure 11a, the second
semiconductor structure 15a, and the third semiconductor structure
15b. A first top electrode 17 and a second top electrode 18 are
respectively formed on the front side of the first semiconductor
structure 11a and the front side of the third semiconductor
structure 15b.
[0016] Next, alternate examples of the method of manufacturing the
light-emitting device 1 are respectively shown in FIG. 2 and FIG.
3.
[0017] Please refer to FIG. 2 for a first example of the method of
manufacturing the light-emitting device 1. The method further
comprises forming a third top electrode 16 on an exposed surface
15s of the second semiconductor structure 15a and applying an
electrical current across the third top electrode 16 and the bottom
electrode 22 to break down the diode character of the second
semiconductor structure 15a. Specifically, a reverse bias is
applied across the third top electrode 16 and the bottom electrode
22 to permanently break down the diode character of the second
semiconductor structure 15a such that the second active layer 152
of the second semiconductor structure 15a is not capable of
emitting light. More specifically, an electrical current ranging
from 80 A/cm.sup.2 to 200 A/cm.sup.2 is injected into the second
semiconductor structure 15a for a duration of time between 0.1 and
0.5 second across the third top electrode 16 and the bottom
electrode 22 to break down the diode behavior of the second
semiconductor structure 15a. As a result, the second semiconductor
structure 15a becomes and function as a resistor having a low
resistance lower than 200 ohms, preferably lower than 100 ohms,
more preferably lower than 10 ohms, and therefore, the second MQW
structure of the second active layer 152 of the second
semiconductor structure 15a is substantially non-luminous even when
forward-biasing the second semiconductor structure 15a. After
finishing all the process steps described above, the light-emitting
device 1 of first embodiment of the present disclosure is formed as
shown in FIG. 2.
[0018] Please refer to FIG. 3 for a second example of the method of
manufacturing the light-emitting device 1. The method further
comprises forming a third top electrode 16 directly on a top
surface 15s and a side surface 15s' of the second semiconductor
structure 15a to short-circuit the second semiconductor structure
15a, and therefore, driving current between the first top electrode
17 and the bottom electrode 22 bypasses the second active layer 152
of the second semiconductor structure 15a to make the second active
layer 152 of the second semiconductor structure 15a incapable of
emitting light during normal operation. After finishing all the
process steps described above, the light-emitting device 1 of
second embodiment of the present disclosure is formed as shown in
FIG. 3.
[0019] The first top electrode 17, the second top electrode 18, the
bottom electrode 22, and the third top electrode 16 comprise metal
material having low electrical resistance, such as Au, Al, Pt, Cr,
Ti, Ni, W, or the combination thereof, and can be formed of a
monolayer or multiple layers. A thickness of the first top
electrode 17, the second top electrode 18, the bottom electrode 22,
or the third top electrode 16 is about 0.1 to 10 microns. The first
top electrode 17 and the second top electrode 18 each has a shape
such as rectangular, polygon, circle, or ellipse from a top view of
the light-emitting device 1. The first top electrode 17, the second
top electrode 18, the bottom electrode 22, and the third top
electrode 16 can be formed by sputtering, vapor deposition, or
plating.
[0020] FIG. 2 shows a sectional view of the light-emitting device 1
in accordance with the first embodiment of the present disclosure.
The light-emitting device 1 comprises a first light-emitting
element 1a and a second light-emitting element 1b. The first
light-emitting element 1a comprises the first semiconductor
structure 11a and the second semiconductor structure 15a, and the
second light-emitting element 1b comprises the third semiconductor
structure 15b. The first light-emitting element 1a and the second
light-emitting element 1b both formed on the carrier 20. The first
light-emitting element 1a comprises the first semiconductor
structure 11a, and the second semiconductor structure 15a formed
between the first semiconductor structure 11a and the carrier 20.
The first active layer 112 of the first semiconductor structure 11a
of the first light-emitting element 1a comprises a first MQW
structure driven by the first top electrode 17 and the bottom
electrode 22 to emit light having a first dominant wavelength
.lamda..sub.1. The second active layer 152 of the second
semiconductor structure 15a of the first light-emitting element 1a
comprises a second MQW structure does not emit light when the first
light-emitting element 1a is driven to emit light having a first
dominant wavelength .lamda..sub.1. The second light-emitting
element 1b comprises a third semiconductor structure 15b formed
above the carrier 20 and next to the first light-emitting element
1a, wherein the second active layer 152 of the third semiconductor
structure 15b comprises a third MQW structure comprising the same
material composition and the same layer sequence as the second MQW
structure of the second semiconductor structure 15a, and the third
MQW structure is driven by the second top electrode 18 and the
bottom electrode 22 to emits light having a second dominant
wavelength .lamda..sub.2. The first MQW structure of the first
semiconductor structure 11a comprises a material or a material
composition different from that of the second MQW structure of the
second semiconductor structure 15a or the third MQW structure of
the third semiconductor structure 15b. The first dominant
wavelength .lamda..sub.1 is different from the second dominant
wavelength .lamda..sub.2. In an example of the embodiment, the
first dominant wavelength .lamda..sub.1 is greater than the second
dominant wavelength .lamda..sub.2. In another example of the
embodiment, the first dominant wavelength .lamda..sub.1 is in the
infrared range and the second dominant wavelength .lamda..sub.2 is
in the red range. In another example of the embodiment, the first
dominant wavelength .lamda..sub.1 and the second dominant
wavelength .lamda..sub.2 are both in the red range.
[0021] The third top electrode 16 is formed on the surface 15s of
the second semiconductor structure 15a. The first top electrode 17
and the bottom electrode 22 provide first electrical current to
forward bias the first MQW structure of the first active layer 112
of the first semiconductor structure 11a to emit light having a
first dominant wavelength .lamda..sub.1. The second top electrode
18 and the bottom electrode 22 provide second electrical current to
forward bias the third MQW structure of the second active layer 152
of the third semiconductor structure 15b to emit light having a
second dominant wavelength .lamda..sub.2, wherein .lamda..sub.1 is
different from .lamda..sub.2. More specifically, the first
light-emitting element 1a only emit the first dominant wavelength
generated in the first MQW structure under an electrical current
100 flowing in series through the first MQW structure and the
second MQW structure, wherein the second MQW structure of the
second active layer 152 of the second semiconductor structure 15a
is non-luminous even when forward-biasing the second semiconductor
structure 15a.
[0022] FIG. 3 shows a sectional view of a light-emitting device 1
in accordance with the second embodiment of the present disclosure.
The elements shown in FIG. 3 denoted by same numbers as the
elements shown in FIG. 2 comprises same structure, material and
functions, and are not addressed again.
[0023] As shown in FIG. 3, the first semiconductor structure 11a
and the second semiconductor structure 15a of the first
light-emitting element 1a form a stepped shape at a surface 15s of
the second semiconductor structure 15a. The third top electrode 16
comprises a contact 161 formed on the top surface 15s of the second
semiconductor structure 15a and a bridge 162 coated on a side
surface 15s' of the second semiconductor structure 15a.
Specifically, the third top electrode 16 abuts the surface of the
second semiconductor structure 15a. The contact 161 is arranged on
the surface 15s of the second semiconductor structure 15a, and the
bridge 162 extends from the contact 161 to the carrier 20 or the
adhesive layer 21. The second MQW structure of the second active
layer 152 of the second semiconductor structure 15a is short
circuited by the third top electrode 16 and disabled from emitting
light. The third top electrode 16 comprise metal material having
low electrical resistance, such as Au, Al, Pt, Cr, Ti, Ni, W, or
the combination thereof, and can be formed of a monolayer or a
multiple layers. The third top electrode 16 provides a series
electrical connection between the first top electrode 17 and the
bottom electrode 22. The third top electrode 16 is directly formed
on the top surface and the side surface of the second semiconductor
structure 15a to short-circuit the second semiconductor structure
15a, and therefore, driving current between the first top electrode
17 and the bottom electrode 22 bypasses the second active layer 152
of the second semiconductor structure 15a to make the second active
layer 152 of the second semiconductor structure 15a incapable of
emitting light during normal operation. The first MQW structure of
the first active layer 112 of the first semiconductor structure 11a
is driven by the first top electrode 17 and the bottom electrode 22
to emit light comprising the first dominant wavelength
.lamda..sub.1. More specifically, the first light-emitting element
1a only emit the first dominant wavelength .lamda..sub.1 generated
in the first MQW structure under an electrical current 200 flowing
in series through the first MQW structure and the second MQW
structure, wherein the second MQW structure is non-luminous.
[0024] As shown in FIGS. 2-3, the light emitting device 1 comprises
the adhesive layer 21 comprising metal material, such as Cu, Al,
Pt, Ti, W, Ag, or the combination thereof. The adhesive layer 21 is
formed between the first light-emitting element 1a and the carrier
20, and/or between the second light-emitting element 1b and the
carrier 20 to reflect the light generated in the first active layer
112 of the first light-emitting element 1a toward to a light
extraction surface of the first light-emitting element 1a distant
from the carrier 20, and/or the light generated in the second
active layer 152 of the second light-emitting element 1b toward a
light extraction surface of the second light-emitting element 1b.
In an embodiment of the present disclosure, the light extraction
efficiency of the first light-emitting element 1a and the second
light-emitting element 1b can be improved the adhesive layer.
[0025] Furthermore, the diode character of the second semiconductor
structure 15a of the first light-emitting element 1a may not
completely be broken down in the first embodiment or the short
circuit formed by the third top electrode 16 (contact 161 and
bridge 162) may not completely block electrical current flowing
through the second active layer 152 of the second semiconductor
structure 15a of the first light-emitting element 1a in the second
embodiment. Some dim light with weak optical output power may be
generated and emitted from the second active layer 152 of the
second semiconductor structure 15a of the first light-emitting
element 1a. Accordingly, the reflective layer 13 is formed between
the first semiconductor layer 151 of the second semiconductor
structure 15a of the first light-emitting element 1a and the second
semiconductor layer 113 of the first semiconductor structure 11a of
the first light-emitting element 1a as shown in FIG. 2 and FIG. 3
to reflect the light generated in the first active layer 112 of the
first semiconductor structure 11a of the first light-emitting
element 1a toward a light extraction surface of the first
semiconductor structure 11a of the first light-emitting element 1a,
and reflect the light generated in the second active layer 152 of
the second semiconductor structure 15a of the first light-emitting
element 1a away from the light extraction surface of the first
semiconductor structure 11a of the first light-emitting element 1a.
In these cases, the second active layer 152 of the second
semiconductor structure 15a of the first light-emitting element 1a
emits an optical output power less than 10% of a total optical
output power of the light-emitting device 1.
[0026] It will be apparent to those having ordinary skill in the
art that various modifications and variations can be made in
accordance with the present disclosure without departing from the
scope or spirit of the disclosure. In view of the foregoing, it is
intended that the present disclosure cover modifications and
variations of this disclosure provided they fall within the scope
of the following claims and their equivalents.
* * * * *