U.S. patent application number 12/458133 was filed with the patent office on 2010-01-07 for light-emitting device and method for manufacturing the same.
This patent application is currently assigned to EPISTAR CORPORATION. Invention is credited to Chia-Liang Hsu.
Application Number | 20100001312 12/458133 |
Document ID | / |
Family ID | 41463688 |
Filed Date | 2010-01-07 |
United States Patent
Application |
20100001312 |
Kind Code |
A1 |
Hsu; Chia-Liang |
January 7, 2010 |
Light-emitting device and method for manufacturing the same
Abstract
A light-emitting device is disclosed. The light-emitting device
comprises a substrate, wherein an ion implanted layer on the top
surface of the substrate; a thin silicon film disposing on the ion
implanted layer; and a light-emitting stack layer on the thin
silicon film. This invention also discloses a method of
manufacturing a light-emitting device comprising providing a
substrate; forming an ion implanted layer on the top surface of the
substrate; providing a light-emitting stack layer; forming a thin
silicon film on the bottom surface of the light-emitting stack
layer; and bonding the light-emitting stack layer to the substrate
with the anodic bonding technique.
Inventors: |
Hsu; Chia-Liang; (Hsinchu,
TW) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE, FOURTH FLOOR
ALEXANDRIA
VA
22314-1176
US
|
Assignee: |
EPISTAR CORPORATION
Hsinchu
TW
|
Family ID: |
41463688 |
Appl. No.: |
12/458133 |
Filed: |
July 1, 2009 |
Current U.S.
Class: |
257/101 ;
257/103; 257/E33.005; 257/E33.017; 438/45 |
Current CPC
Class: |
H01L 33/0093 20200501;
H01L 33/025 20130101 |
Class at
Publication: |
257/101 ; 438/45;
257/103; 257/E33.017; 257/E33.005 |
International
Class: |
H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 2008 |
TW |
097124823 |
Jul 24, 2008 |
CN |
200810134353.5 |
Claims
1. A method of manufacturing a light-emitting device comprising the
steps of: providing a first substrate; forming a light-emitting
stack layer on the first substrate; forming a thin silicon film on
the light-emitting stack layer; providing a second substrate
disposed on the thin silicon film; forming an ion implanted layer
on the second substrate; providing an electrode potential
difference to form an oxide layer between the thin silicon film and
the ion implanted layer; and removing the first substrate.
2. The method of manufacturing a light-emitting device according to
claim 1, wherein the step of forming the light-emitting stack layer
further comprising the steps of: forming a first-type conductivity
semiconductor layer on the first substrate; forming a
light-emitting layer on the first-type conductivity semiconductor
layer; and forming a second-type conductivity semiconductor layer
on the light-emitting layer.
3. The method of manufacturing a light-emitting device according to
claim 1, further comprising the step of forming at least an
electrode on the light-emitting stack layer.
4. The method of manufacturing a light-emitting device according to
claim 1, wherein the step of forming the ion implanted layer is a
step of forming a patterned ion implanted layer.
5. The method of manufacturing a light-emitting device according to
claim 4, wherein the patterned ion implanted layer further
comprising patterns selected from the group consisting of a regular
symmetry pattern and an irregular asymmetry pattern.
6. The method of manufacturing a light-emitting device according to
claim 4, wherein the patterned ion implanted layer covers about 15%
to 85% of the surface area of the second substrate.
7. The method of manufacturing a light-emitting device according to
claim 4, wherein the patterned ion implanted layer covers about 30%
to 60% of the surface area of the second substrate.
8. The method of manufacturing a light-emitting device according to
claim 1, wherein the step of forming an ion implanted layer on the
second substrate is proceeded in an oxygen-containing environment,
and the ions implanted in the ion implanted layer comprises sodium
ions.
9. The method of manufacturing a light-emitting device according to
claim 1, further comprising a step of thermal driving the ion
implanted layer in an oxygen-containing environment.
10. The method of manufacturing a light-emitting device according
to claim 1, wherein the electrode potential difference is between
500 volts to 1200 volts.
11. A light-emitting device, comprising: a substrate, wherein a
surface of the substrate comprising an ion implanted layer; a
light-emitting stack layer disposed on the ion implanted layer; and
an adhesive layer, connecting the substrate with the light-emitting
stack layer, wherein the adhesive layer at least comprises a thin
silicon film disposed between the ion implanted layer and the
light-emitting layer.
12. A light-emitting device according to claim 11, wherein the
adhesive layer is a multi-layer structure.
13. A light-emitting device according to claim 11, wherein the
adhesive layer further comprising an oxide layer disposed between
the ion implanted layer and the thin silicon film.
14. A light-emitting device according to claim 11, wherein the
light-emitting stack layer further comprising: a first-type
conductivity semiconductor layer disposed on the thin silicon film;
a light-emitting layer disposed on the first-type conductivity
semiconductor layer; and a second-type conductivity semiconductor
layer disposed on the light-emitting layer.
15. A light-emitting device according to claim 14, further
comprising a first electrode and a second electrode respectively
disposed on the first-type conductivity semiconductor layer and the
second-type conductivity semiconductor layer.
16. A light-emitting device according to claim 11, wherein the ion
implanted layer comprises sodium ions.
17. A light-emitting device according to claim 11, wherein the ion
implanted layer is a patterned ion implanted layer.
18. A light-emitting device according to claim 17, wherein the
patterned ion implanted layer further comprising patterns selected
from the group consisting of a regular symmetry pattern and an
irregular asymmetry pattern.
19. A light-emitting device according to claim 17, wherein the
patterned ion implanted layer covers about 15% to 85% of the
surface area of the second substrate.
20. A light-emitting device according to claim 17, wherein the
patterned ion implanted layer covers about 30% to 60% of the
surface area of the second substrate.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application claims the right of priority based on TW
application Ser. No. 097124823, filed "Jul. 1, 2008", entitled
"Light-emitting Device and Method for Manufacturing the Same" and
the contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The application relates to a light-emitting device, and more
particularly to a light-emitting diode having an ion implanted
layer on the top surface of a substrate.
BACKGROUND
[0003] The light-emitting diode (LED) emits light by transforming
the energy released from the electrons moving between the n-type
semiconductor and the p-type semiconductor so the mechanism is
different from that of the incandescent lamp. Thus, the LED is
called cold light source. In addition, because the LED has
advantages like high reliability, long lifetime, compact size, low
power consumption, and so on, the current illumination market
expects the LED to be an illuminant tool of the new generation.
[0004] The conventional LED structure is a semiconductor epitaxial
structure formed on a substrate, wherein the quality of the epitaxy
in the semiconductor epitaxial structure has critical influence on
the internal quantum efficiency of the LED, and whether the lattice
constant of the substrate can match with that of the material of
the epitaxial structure is important to the quality of the epitaxy.
Therefore, the choice of the substrate materials for the LED is
limited.
[0005] In addition, to improve the light extraction efficiency and
heat-dissipation of the LED, the technique of transferring the
substrate of the LED comes up gradually. Referring to FIG. 1A to
FIG. 1G, a flowchart for a conventional substrate transfer process
is illustrated. As shown in FIG. 1A, a first substrate 10 is
provided, and an epitaxial structure 12 is provided as shown in
FIG. 1B. Referring to FIG. 1C, then a second substrate 14 is
provided, and an adhesive layer 16 is, referring to FIG. 1D, formed
on the second substrate 14. Later, referring to FIG. 1E, the
structure illustrated in FIG. 1A is flipped to attach the epitaxial
structure 12 with the second substrate 14 with the adhesive layer
16 by pressed lamination, wherein the material of the adhesive
layer 16 can be metal or polymers like PI, BCB, PFCB, and
combinations thereof. After that, referring to FIG. 1F, the
substrate 10 is removed so as to form a conventional light-emitting
diode structure illustrated in FIG. 1G.
SUMMARY
[0006] The present application provides a light-emitting device
including an epitaxial structure and a substrate wherein the
substrate of the LED has an ion implanted layer to alter refractive
index of the substrate surface. Therefore, the refractive index has
a gradual distribution between the epitaxial structure and the
substrate so as to reduce total internal reflection effect.
[0007] The present application provides a method for manufacturing
LED by bonding the epitaxial structure to the substrate with the
anodic bonding technology.
[0008] Other features and advantages of the present application and
variations thereof will become apparent from the following
description, drawing and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings incorporated herein provide a
further understanding of the invention therefore constitute a part
of this specification. The drawings illustrating embodiments of the
invention, together with the description, serve to explain the
principles of the invention.
[0010] FIGS. 1A-1G are the diagrams illustrating the manufacturing
procedure of the conventional light-emitting diode.
[0011] FIGS. 2A-2H are the diagrams illustrating the manufacturing
procedure of the light-emitting diode in accordance with one
embodiment of the present application.
[0012] FIGS. 3A-3E are the diagrams illustrating the manufacturing
procedure of the light-emitting diode in accordance with another
embodiment of the present application.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0013] FIGS. 2A-2H are the diagrams illustrating the manufacturing
procedure in accordance with one embodiment of the present
application, including the following steps: as shown in FIG. 2A,
providing a first substrate 30, and as shown in FIG. 2B, forming a
light-emitting stack layer 32 by MOCVD (Metal Organic Chemical
Vapor Deposition), wherein the light-emitting stack layer 32
includes at least a firs-type conductivity semiconductor layer 320,
a lighting-emitting layer 322, and a second-type conductivity
semiconductor layer 324 from top to bottom, wherein the material of
the light-emitting stack layer 32 can be semiconductor materials
such as GaAlAs, AlGaInP, GaP or GaN series and combinations
thereof. The material of the first substrate 30 can be materials
having lattice constant matching with the lattice constant of the
light-emitting stack layer 32, such as Sapphire, SiC, GaAs, and so
on. In this embodiment, a substrate of SiC and a light-emitting
stack layer of GaN are adopted for exemplifying.
[0014] Thereafter, as shown in FIG. 2C, a thin silicon film 34 is
formed on the light-emitting stack layer 32 by PECVD
(Plasma-enhanced Chemical Vapor Deposition), wherein the material
of the thin silicon film 34 in this embodiment is amorphous silicon
with a width of 200 nm.
[0015] As shown in 2D, the manufacturing procedure further
comprises the following steps: providing a second substrate 36,
wherein the material of the second substrate 36 could be Oxides
such as Sapphire or ZnO, and a Sapphire substrate is used as
exemplary in this embodiment, and form an ion implanted layer 38 by
implanting sodium ions from the upper side into the second
substrate 36 through ion implantation technique, wherein sodium
ions in the ion implanted layer 38 are combined with oxygen ions of
the Sapphire substrate to form Na.sub.xO molecules.
[0016] After that, as shown in FIG. 2E, the manufacturing procedure
further comprises the steps of flipping the structure shown in FIG.
2C, disposing it on the ion implanted layer 38 to contact the thin
silicon layer 34 with the ion planted layer 38; and providing a
voltage between the thin silicon layer 34 and the ion implanted
layer 38 wherein the voltage is about 500 to 1200 volts, and the
electric potential of the thin silicon layer 34 is higher than the
electric potential of the ion implanted layer 38. Due to the
electric potential difference between the thin silicon layer 34 and
the ion planted layer 38, the oxygen ions of the Na.sub.xO
molecules in the ion planted layer 38 are forced to move toward the
thin silicon layer 34 and form an oxide layer 40 with the thin
silicon layer 34 in the interface between the ion planted layer 38
and the thin silicon layer 34. Therefore, an adhesive layer 41 is
formed by the thin silicon layer 34 and the oxide layer 40, and the
light-emitting stack layer 32 is attached to the second substrate
36. In this embodiment, the material of the oxide layer 40 is
SiO.sub.2.
[0017] Then, as shown in FIG. 2F, the manufacturing procedure
further comprises the steps of removing the first substrate 30 as
shown in FIG. 2G, etching part of the light-emitting stack layer 32
by lithography technique to expose part of first-type conductivity
semiconductor layer 320 as shown in FIG. 2H, forming a first
electrode 42 and a second electrode 44 on the first-type
conductivity semiconductor layer 320 and the second-type
conductivity semiconductor layer 324 respectively for electrical
connection so as to form a light-emitting diode chip 200.
[0018] Moreover, in the step of forming the ion implanted layer 38,
the second substrate 36 can be disposed in an oxygen-containing
environment so the concentration of the Na.sub.xO molecules in the
ion planted layer 38 is increased. In a preferred embodiment, the
second substrate 36 is disposed in an environment with sufficient
oxygen to perform the step of forming the ion implanted layer 38.
In addition, after forming the ion planted layer 38, the second
substrate 36 can be disposed in an oxygen-containing environment
for moving the oxygen ions into the ion implanted layer 38 to
increase the content of Na.sub.xO molecules in the ion planted
layer 38 by thermal driving method, wherein a preferred embodiment
of above thermal driving step is performed with the second
substrate 36 disposed in an environment with sufficient oxygen.
[0019] In this embodiment, the refractive index of the
light-emitting stack layer 32 is about 3.4, the refractive index of
the second sapphire substrate 36 is about 1.78, and the refractive
index of the ion implanted layer 38 implanted by sodium ions is
between the refractive indexes of the light-emitting stack layer 32
and the second sapphire substrate 36, for example, about 1.8 to
2.0. Accordingly, when a light is emitted from the light-emitting
stack layer 32, it is out of the LED chip 200 after passing the ion
implanted layer 38 and the second sapphire substrate 36. Therefore,
the refractive index of above light path is gradually altered from
higher value to lower one so as to reduce the total internal
reflection effect of light and raise the light extraction
efficiency of the LED chip 200.
[0020] FIGS. 3A-3E are the diagrams illustrating the manufacturing
procedure in accordance with another embodiment of the present
application. As shown in FIG. 3A, the manufacturing procedure
comprises the steps of providing a second substrate 36 and forming
a patterned ion implanting layer 50 on the surface of the second
substrate 36. The patterned ion implanting layer 50 has regular
symmetry or irregular asymmetry patterns, wherein a regular
symmetry patterned ion planting layer is defined as a patterned ion
planting layer showing identical reduplicating characteristics in
any direction of the surface of the second sapphire substrate 36,
and the term "regular" could be defined as periodic, varied
periodic, quasiperodicity or combinations thereof. The irregular
asymmetry patterned ion planting layer is defined as a patterned
ion planting layer unable to show identical reduplicating
characteristics in any direction of the surface of the second
sapphire substrate 36. Additionally, in this embodiment, the ion
planting layer 50 covers about 15% to 85% of the surface area of
the second substrate 36, and the better is 30% to 60% of the
surface area. Furthermore, in this ion implanted step, ion source
at least comes from sodium ions and the ion source sodium ions
forms Na.sub.xO molecules in the patterned ion planting layer
50.
[0021] After that, as shown in FIG. 3B, the manufacturing procedure
further comprises the steps of flipping the structure illustrated
in FIG. 2C to contact the thin silicon layer 34 with the second
substrate 36 and the patterned ion planting layer 50; providing a
voltage among the patterned ion implanting layer 50, the thin
silicon layer 34 and the second substrate 36, wherein the voltage
is about 500 to 1200 volts in this step, and the electric potential
of the thin silicon layer 34 is higher than the electric potential
of the patterned ion implanting layer 50. Due to the electric
potential difference between the thin silicon layer 34 and the
patterned ion implanting layer 50, the oxygen ions of the Na.sub.xO
molecules in the patterned ion implanting layer 50 are forced to
move toward the thin silicon layer 34 and form an oxide layer 52 in
the interface between the patterned ion implanting layer 50 and the
thin silicon layer 34. Therefore, an adhesive layer 53 is formed by
the thin silicon layer 34 and the oxide layer 52, and the
light-emitting stack layer 32 is attached to the second substrate
36. In this embodiment, the material of the oxide layer 52 is
SiO.sub.2.
[0022] Then, as shown in FIG. 3C, the manufacturing procedure
further comprises the steps of removing the first substrate 30;
etching part of the light-emitting stack layer 32, as shown in FIG.
3D, to expose part of the first-type conductivity semiconductor
layer 320 by lithography technique. Finally, as shown in FIG. 3E,
forming a first electrode 42 and a second electrode 44 on the
first-type conductivity semiconductor layer 320 and the second-type
conductivity semiconductor layer 324 respectively for electrically
connecting the first electrode with the first conductivity
semiconductor layer and the second electrode with the second
conductivity semiconductor layer so as to form a light-emitting
diode chip 300.
[0023] In this embodiment, the material of the second substrate 36
is Sapphire with the refractive index of about 1.78, and the
refractive index of the patterned ion implanting layer 50 implanted
by sodium ions, for example, on the surface of the second sapphire
substrate 36, is about 1.8 to 2.0. The refractive index difference
between the material of the second substrate 36 and the patterned
ion implanting layer 50 reduces the total internal reflection
effect of light emitted from the light-emitting stack layer 32 in
the LED chip 300 so as to further increase the luminescent
extraction efficiency.
[0024] The foregoing description has been directed to a specific
embodiment of this invention. It will be apparent; however, that
other variations and modifications may be made to the described
embodiments, with the attainment of some or all of their
advantages. Therefore, it is the object of the appended claims to
cover all such variations and modifications that fall within the
spirit and scope of the invention.
* * * * *