U.S. patent application number 14/594761 was filed with the patent office on 2015-05-07 for light emitting device.
The applicant listed for this patent is Epistar Corporation. Invention is credited to Kuen-Ru CHUANG, Min-Hsun HSIEH, Chao-Nien HUANG, Ming-Jiunn JOU, Chia-Cheng LIU, Chih-Chiang LU, Shu-Wen SUNG, Shane-Shyan WEY.
Application Number | 20150123151 14/594761 |
Document ID | / |
Family ID | 21678661 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150123151 |
Kind Code |
A1 |
HSIEH; Min-Hsun ; et
al. |
May 7, 2015 |
LIGHT EMITTING DEVICE
Abstract
A light-emitting structure includes a transparent substrate; a
first transparent conductive layer formed on the transparent
substrate and having a first top surface and a second top surface
substantially coplanar with the first top surface; a first
light-emitting stack formed on the first top surface; and a first
electrode directly formed on the second top surface.
Inventors: |
HSIEH; Min-Hsun; (Hsinchu,
TW) ; CHUANG; Kuen-Ru; (Hsinchu, TW) ; SUNG;
Shu-Wen; (Hsinchu, TW) ; LIU; Chia-Cheng;
(Hsinchu, TW) ; HUANG; Chao-Nien; (Hsinchu,
TW) ; WEY; Shane-Shyan; (Hsinchu, TW) ; LU;
Chih-Chiang; (Hsinchu, TW) ; JOU; Ming-Jiunn;
(Hsinchu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Epistar Corporation |
Hsinchu |
|
TW |
|
|
Family ID: |
21678661 |
Appl. No.: |
14/594761 |
Filed: |
January 12, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13730130 |
Dec 28, 2012 |
8932885 |
|
|
14594761 |
|
|
|
|
13114384 |
May 24, 2011 |
8344353 |
|
|
13730130 |
|
|
|
|
11724310 |
Mar 15, 2007 |
RE42422 |
|
|
13114384 |
|
|
|
|
09683959 |
Mar 6, 2002 |
6867426 |
|
|
11724310 |
|
|
|
|
Current U.S.
Class: |
257/88 ;
257/99 |
Current CPC
Class: |
H01L 33/42 20130101;
H01L 33/30 20130101; H01L 33/32 20130101; H01L 33/0093 20200501;
H01L 33/16 20130101; H01L 33/02 20130101; H01L 21/2007
20130101 |
Class at
Publication: |
257/88 ;
257/99 |
International
Class: |
H01L 33/16 20060101
H01L033/16; H01L 33/42 20060101 H01L033/42 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2001 |
TW |
090115871 |
Claims
1. A light-emitting structure, comprising: a transparent substrate:
a first transparent conductive layer formed on the transparent
substrate and having a first top surface and a second top surface
substantially coplanar with the first top surface; a first
light-emitting stack formed on the first top surface; and a first
electrode directly formed on the second top surface.
2. The light-emitting structure of claim 1, further comprising a
second transparent conductive layer electrically connected to the
light-emitting stack.
3. The light-emitting structure of claim 2, wherein the first
transparent conductive layer and the second transparent conductive
layer comprises a same material.
4. The light-emitting structure of claim 2, further comprising a
second electrode formed on the second transparent conductive
layer.
5. The light-emitting structure of claim 2, wherein the first
light-emitting stack comprises a semiconductor layer with a width
equal to that of the second transparent conductive layer.
6. The light-emitting structure of claim 2, wherein the first
transparent conductive layer, the second transparent conductive
layer or both comprise ITO.
7. The light-emitting structure of claim 1, further comprising a
second light-emitting stack formed on the first transparent
conductive layer.
8. The light-emitting structure of claim 1, wherein the first
transparent conductive layer is a non-semiconductor layer.
9. The light-emitting structure of claim 1, wherein the transparent
substrate comprises sapphire, GaP or glass.
10. The light-emitting structure of claim 1, wherein the first
light-emitting stack comprises a semiconductor layer with a width
less than that of the first transparent conductive layer.
11. The light-emitting structure of claim 1, wherein the first
transparent conductive layer is an amorphous layer.
12. The light-emitting structure of claim 1, wherein the first top
surface and the second top surface are flat.
13. The light-emitting structure of claim 1, wherein the first
transparent conductive layer is a non-epitaxial layer.
Description
RELATED APPLICATION
[0001] This application is a continuation application of U.S.
patent application Ser. No. 13/730,130, entitled "LIGHT EMITTING
DIODE HAVING A TRANSPARENT SUBSTRATE", filed Dec. 28, 2012, which
is a divisional application of U.S. patent application Ser. No.
13/114,384, entitled "LIGHT EMITTING DIODE HAVING A TRANSPARENT
SUBSTRATE", filed May 24, 2011, which is a continuation application
of U.S. patent application Ser. No. 11/724,310, entitled "LIGHT
EMITTING DIODE HAVING A TRANSPARENT SUBSTRATE", filed Mar. 15, 2007
claiming the right of priority based on Taiwan application Ser. No.
090115871, filed Jun. 27, 2001; the content of which is
incorporated herein by reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a light-emitting device,
more specifically to a light-emitting device with a light-emitting
stack on a transparent conductive layer.
DESCRIPTION OF BACKGROUND ART
[0003] Light emitting diodes (LEDs) are employed in a wide variety
of applications including optical display devices, traffic lights,
data storage equipment, communication devices, illumination
apparatuses, and medical treatment equipment. Some of the main
goals of engineers who design LEDs are to increase the brightness
of the light emitted from LEDs and to reduce the cost of
manufacturing LEDs.
[0004] U.S. Pat. No. 5,783,477 discloses a method of bonding two
compound semiconductor surfaces to produce an ohmic contact
interface. The method of manufacturing a prior art LED is to create
an ohmic contact interface by aligning the crystallographic
orientation and rotational alignment of two semiconductor surfaces
and applying uniaxial pressure to the semiconductor wafers at a
temperature of 1000.degree. C. In actual procedure, however, it is
difficult and expensive to align the crystallographic orientation
and rotational alignment of the two semiconductor surfaces.
SUMMARY OF THE DISCLOSURE
[0005] A light-emitting structure includes a transparent substrate;
a first transparent conductive layer formed on the transparent
substrate and having a first top surface and a second top surface
substantially coplanar with the first top surface; a first
light-emitting stack formed on the first top surface; and a first
electrode directly formed on the second top surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a cross sectional view of a high brightness light
emitting diode having a transparent substrate according to the
first embodiment of the present invention.
[0007] FIG. 2 is a cross sectional view showing a first
semiconductor multilayer before wafer bonding during the
manufacturing method according to the present invention.
[0008] FIG. 3 is a cross sectional view showing an amorphous
interface layer and a second semiconductor multilayer before wafer
bonding during the manufacturing method according the present
invention.
[0009] FIG. 4 is a cross sectional view showing a third
semiconductor multilayer after wafer bonding, but before removal of
the non-transparent substrate during the manufacturing method
according the present invention.
[0010] FIG. 5 is a cross sectional view showing a third
semiconductor multilayer after removal of the non-transparent
substrate and formation of an ITO transparent conductive layer
during the manufacturing method according the present
invention.
[0011] FIG. 6 is a cross sectional view of a high brightness light
emitting diode having a transparent substrate according to the
second embodiment of the invention.
[0012] FIG. 7 is a cross sectional view of a high brightness light
emitting diode having a transparent substrate according to the
third embodiment of the invention.
[0013] FIG. 8 is a cross sectional view of a high brightness light
emitting diode having a transparent substrate according to the
fourth embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0014] FIG. 1 is a cross sectional view of a high brightness light
emitting diode (LED) 1 having a transparent substrate according to
the first embodiment of the present invention. In the LED 1, an
indium tin oxide (ITO) amorphous interface layer 11 is formed on a
sapphire transparent substrate 10. A top surface of the ITO
amorphous interface layer 11 comprises a first surface region and a
second surface region. The LED further comprises layers stacked
upon each other on the first surface region in the following order,
bottom to top: a contact layer of p+-type GaAs 12, a cladding layer
of a p-type AlGaInP 13, a multiple quantum well (MQW)
light-emitting layer 14, a cladding layer of n-type AlGaInP 15, a
stop layer of n-type AlGaAs 16, and an ITO transparent conductive
layer 18. A first electrode 19 is located on the ITO transparent
conductive layer 18, and a second electrode 20 is located on the
second surface region.
[0015] FIG. 2 and FIG. 3 illustrate a method for manufacturing the
light emitting diode 1 according to the first embodiment of the
present invention. A first semiconductor multilayer 2 is created by
first forming an n-type stop layer 16 of AlGaAs on an n-type GaAs
semiconductor substrate 17. Then an n-type cladding layer 15 of
AlGaInP is formed on the n-type stop layer 16. An MQW
light-emitting layer 14 of AlGaInP is formed on the n-type cladding
layer 15. A p-type cladding layer 13 of AlGaInP is formed on the
MQW light-emitting layer 14, and a p+-type contact layer 12 of GaAs
is formed on the p-type cladding layer 13. Next, a second
semiconductor multilayer 3 is created. The second semiconductor
multilayer 3 comprises an amorphous interface layer 11 of ITO
formed on a sapphire substrate 10. As is shown in FIG. 4, a third
semiconductor multilayer 4 is produced by inverting the first
semiconductor multilayer 2, placing it on the semiconductor
multilayer 3, and bonding the first semiconductor multilayer 2 to
the second semiconductor multilayer 3 by elevating temperature and
applying uniaxial pressure to the semiconductor multilayers. FIG. 4
and FIG. 5 show the next step, which comprises the removal of the
n-type GaAs semiconductor substrate 17 from the multilayer 4 and
the formation of a first ITO transparent conductive layer 18 on the
n-type stop layer 16, producing a fourth semiconductor multilayer
5. Next, an interface exposed region is formed by etching away a
portion of the fourth semiconductor multilayer 5 from the first ITO
transparent conductive layer 18 to the ITO amorphous interface
layer 11. Finally, a first contact electrode 19 and a second
contact electrode 20 are formed on the first ITO transparent
conductive layer 18 and the interface exposed region,
respectively.
[0016] FIG. 6 illustrates a light emitting diode 6 having a
transparent substrate according to a second preferred embodiment of
the present invention. A transparent substrate 611 of p-type GaP is
formed on an ohmic contact electrode 610. A first p+-type contact
layer 612 of GaAs is formed on the transparent substrate 611. An
indium tin oxide (ITO) amorphous interface layer 613 is formed on
the first p+-type contact layer 612. A second p+-type contact layer
614 of GaAs is formed on the ITO amorphous interface layer 613. A
p-type cladding layer 615 of AlGaInP is formed on the second
p+-type contact layer 614. A multiple quantum well (MQW)
light-emitting layer 616 of AlGaInP is formed on the p-type
cladding layer 615. An n-type cladding layer 617 of AlGaInP is
formed on the MQW light-emitting layer 616. An n-type stop layer
618 of AlGaAs is formed on the n-type cladding layer 617. An ITO
transparent conductive layer 619 is formed on the n-type stop layer
618. An electrode 620 is formed on the ITO transparent conductive
layer 619.
[0017] FIG. 7 illustrates a light emitting diode 7 having a
transparent substrate according to a third preferred embodiment of
the present invention. A transparent substrate 711 of n-type GaP is
formed on a first electrode 710. An indium tin oxide (ITO)
amorphous interface layer 713 is formed on the transparent
substrate 711. An n-type contact layer 714 of GaP is formed on the
ITO amorphous interface layer 713. An n-type cladding layer 715 of
AlGaInP is formed on the n-type contact layer 714. A multiple
quantum well (MQW) light-emitting layer 716 of AlGaInP is formed on
the n-type cladding layer 715. A p-type cladding layer 717 of
AlGaInP is formed on the MQW light-emitting layer 716. A p-type
buffer layer 718 of AlGaAs is formed on the p-type cladding layer
717. A p+-type contact layer 719 of GaAs is formed on the p-type
buffer layer. An ITO transparent conductive layer 720 is formed on
the p+-type contact layer 719. A second electrode 721 is formed on
the ITO transparent conductive layer 720.
[0018] FIG. 8 illustrates a light emitting diode 8 having a
transparent substrate according to a fourth preferred embodiment of
the present invention. An indium tin oxide (ITO) amorphous
interface layer 811 is formed on a transparent substrate 810 of
glass. A top surface of the ITO amorphous interface layer 811
comprises a first surface region and a second surface region. An
n+-type reverse tunneling contact layer 814 of InGaN is formed on
the first surface region. A p-type cladding layer 815 of GaN is
formed on the n+-type reverse tunneling contact layer 814. A
multiple quantum well (MQW) light-emitting layer 816 of InGaN is
formed on the p-type cladding layer 815. An n-type cladding layer
817 of GaN is formed on the MQW light-emitting layer 816. A first
Ti-Al contact electrode is formed on the n-type cladding layer 817.
A second electrode 820 is formed on the second surface region.
[0019] According to the description of these embodiments, LEDs
having a transparent substrate can be manufactured by a method of
bonding two chips using an amorphous interface layer. LEDs made
according to the present invention are easier to manufacture, less
expensive to manufacture, and brighter than those made according to
the prior art.
[0020] While the invention has been disclosed and described with
reference to these preferred embodiments, the scope of the
invention is not limited to these preferred embodiments. Any
variation and modifications of the invention still falls within the
spirit and scope of the invention. For example, using a transparent
conductive layer of adhesive agent instead of a single-crystal
interface layer or using a single quantum well light-emitting layer
instead of a multiple quantum well light-emitting layer cannot
escape the scope and spirit of the invention. Moreover, the
manufacturing method of the present invention is also suitable for
manufacturing a light emitting diode having a non-transparent
substrate.
[0021] Those skilled in the art will readily observe that numerous
modifications and alterations of the device may be made while
retaining the teachings of the invention.
[0022] Accordingly, the above disclosure should be construed as
limited only by the metes and bounds of the appended claims.
* * * * *