U.S. patent application number 11/790096 was filed with the patent office on 2008-07-24 for method of uniform current distribution using current modified layer.
This patent application is currently assigned to National Central University. Invention is credited to Pen-ko Chou, Te-Yuan Chung, Ching-Liang Lin, Cheng-yi Liu.
Application Number | 20080176354 11/790096 |
Document ID | / |
Family ID | 39640358 |
Filed Date | 2008-07-24 |
United States Patent
Application |
20080176354 |
Kind Code |
A1 |
Liu; Cheng-yi ; et
al. |
July 24, 2008 |
Method of uniform current distribution using current modified
layer
Abstract
An electric device has a p-n diode, where the p-n diode is
covered with a current modified layer (CML). With a resistance
distribution of the CML, a current is decreased toward all
directions from a point on a bonding pad between the CML and the
p-n diode. Hence, a current is uniformly distributed on the CML by
fine tuning the resistance distribution. Thus, an effectiveness of
the electric device is improved.
Inventors: |
Liu; Cheng-yi; (Jungli City,
TW) ; Chung; Te-Yuan; (PingTung City, TW) ;
Chou; Pen-ko; (Taipei City, TW) ; Lin;
Ching-Liang; (Taoyuan City, TW) |
Correspondence
Address: |
TROXELL LAW OFFICE PLLC;SUITE 1404
5205 LEESBURG PIKE
FALLS CHURCH
VA
22041
US
|
Assignee: |
National Central University
Taoyuan County
TW
|
Family ID: |
39640358 |
Appl. No.: |
11/790096 |
Filed: |
April 23, 2007 |
Current U.S.
Class: |
438/48 ;
257/E29.09; 257/E29.091; 257/E29.189; 257/E31.119; 438/116 |
Current CPC
Class: |
H01L 29/205 20130101;
H01L 29/7371 20130101; H01L 29/201 20130101 |
Class at
Publication: |
438/48 ; 438/116;
257/E31.119 |
International
Class: |
H01L 21/3205 20060101
H01L021/3205 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2007 |
TW |
096101956 |
Claims
1. A method of a uniform current distribution using a current
modified layer, comprising steps of: (a) obtaining a semiconductor
with a p-n junction; and (b) deposing a resistance-varied
transparent conducting layer on said semiconductor with said p-n
junction to spread current.
2. The method according to claim 1, wherein said method is applied
to an electric device; and wherein said electric device is selected
from a group consisting of a light emitting display (LED), a solar
cell, an organic LED (OLED), a liquid crystal display (LCD) and a
touch panel.
3. The method according to claim 1, wherein said semiconductor with
said p-n junction has a structure selected from a group consisting
of an n-side up structure and a p-side up structure.
4. The method according to claim 1, wherein said semiconductor with
said p-n junction has a structure selected from a group consisting
of a structure of pairs of multiple-quantum-well (MQW) and a
structure of layers of heterostructures and p-type-intrinsic-n-type
(p-i-n) optical detector structures.
5. The method according to claim 1, wherein said semiconductor with
said p-n junction is made of at least one III-V material; and
wherein said III-V material is selected from a group consisting of
GaAs, In P, GaN, AlGaN, AlN, GaInN, AlGaInN, InN, GaInAsN and
GaInPN
6. The method according to claim 1, wherein said semiconductor with
said p-n junction is made of a silicon selected from a group
consisting of a monocrystalline silicon, a multicrystalline silicon
and an amorphous silicon.
7. The method according to claim 1, wherein said resistance-varied
transparent conducting layer is flat and is transparent.
8. The method according to claim 1, wherein said resistance-varied
transparent conducting layer is selected from a group consisting of
a p-type semiconductor, an n-type semiconductor and an
insulator.
9. The method according to claim 1, wherein said resistance-varied
transparent conducting layer is made of a metal oxide.
10. The method according to claim 1, wherein said resistance-varied
transparent conducting layer is transparent to visible light,
infrared and ultraviolet.
11. The method according to claim 1, wherein said resistance-varied
transparent conducting layer is adhered to said semiconductor with
said p-n junction in a way selected from a group consisting of
above a p-type semiconductor of said semiconductor with a p-n
junction, beneath said p-type semiconductor of said semiconductor
with a p-n junction, above an n-type semiconductor of said
semiconductor with a p-n junction, and beneath said n-type
semiconductor of said semiconductor with a p-n junction,
12. The method a according to claim 1, wherein said
resistance-varied transparent conducting layer on said
semiconductor with said p-n junction has an overall thickness
selected from a group consisting of a uniform overall thickness or
a non-uniform overall thickness.
13. The method according to claim 1, wherein said resistance-varied
transparent conducting layer with said uniform overall thickness
has a resistance being varied in a horizontal direction; and
wherein a variable resistance coefficient of said resistance-varied
transparent conducting layer has a correlation to a position on
said resistance-varied transparent conducting layer related to a
point on a bonding pad between said resistance-varied transparent
conducting layer and said semiconductor with said p-n junction.
14. The method according to claim 13, wherein said variable
resistance coefficient is obtained from a function; and wherein
said function includes a discontinuous function.
15. The method according to claim 12, wherein said
resistance-varied transparent conducting layer with said
non-uniform overall thickness varies resistance in a horizontal
direction according to a thickness at a position on said
resistance-varied transparent conducting layer; and wherein a
variable resistance coefficient and said thickness at said position
on said resistance-varied transparent conducting layer have
correlations to said position on said resistance-varied transparent
conducting layer related to a point on a bonding pad between said
resistance-varied transparent conducting layer and said
semiconductor with said p-n junction.
16. The method according to claim 15, wherein said thickness at
said position on said resistance-varied transparent conducting
layer, and said variable resistance coefficient are obtained from
functions; and wherein said functions include a discontinuous
function.
17. The method according to claim 1, wherein said resistance-varied
transparent conducting layer further comprises a layer selected
from a group consisting of a metal layer and a resistance layer;
and wherein said layer has a non-uniform density.
18. The method according to claim 17, wherein said metal layer is
selected from a group consisting of a p-type semiconductor and an
n-type semiconductor.
19. The method according to claim 17, wherein said resistance layer
is selected from a group consisting of a p-type semiconductor, an
n-type semiconductor and a nonconductor.
20. The method according to claim 1, wherein said resistance-varied
transparent conducting layer is further roughened on surface.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a current distribution;
more particularly, relates to obtaining a current modified layer
(CML) to uniformly distribute a current and to thus improve an
effectiveness of an electric device.
DESCRIPTION OF THE RELATED ART
[0002] For flexible electric devices, a transparent conducting
layer has a good conductivity and a 80% transparency to visible
light. Therefore, the transparent conducting layer is widely used
to fabricate electrodes of electro-optical devices, like solar
cell, a flat panel display, an organic light emitting display
(OLED), a touch screen, etc. As is well known, chemical
composition, structure, crystallization, surface status and
mechanics of the electro-optical device has direct impacts on its
characteristics and effectiveness. Since semiconductor technologies
are improving, the transparent conducting layer is more widely
used; and its utilization in a display even becomes a hot research
topic in the electro-optical industry.
[0003] Up to now, the transparent conducting layer is mostly used
as a conductive electrode; and the transparent conductive electrode
is usually used in a p-side up LED to improve a current
distribution of an electrode. However, when the transparent
conductive electrode is used in a thin GaN structure, the
improvement on current distribution is not as good as when used in
the p-side up LED. Hence, the prior art does not fulfill all users'
requests on actual use.
SUMMARY OF THE INVENTION
[0004] The main purpose of the present invention is to obtain a CML
to uniformly distribute a current and to thus improve an
effectiveness of an electric device.
[0005] To achieve the above purpose, the present invention is a
method of a uniform current distribution using a CML, comprising
steps of (a) obtaining a semiconductor with a p-n junction; and (b)
deposing a resistance-varied transparent conducting layer as a CML
on the semiconductor with the p-n junction, where a metal layer or
resistance layer with a non-uniform density can be further deposed
on the resistance-varied transparent conducting layer; the
resistance-varied transparent conducting layer can be further
roughened on surface; the resistance-varied transparent conducting
layer is a p-type semiconductor, an n-type semiconductor or a
insulator; the metal layer is a p-type semiconductor or an n-type
semiconductor; the resistance layer is a p-type semiconductor an
n-type semiconductor or a nonconductor; and the resistance-varied
transparent conducting layer as a CML spreads current for obtaining
a uniformly distributed current and thus for an improved
effectiveness. Accordingly, a novel method of a uniform current
distribution using a CML is obtained.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0006] The present invention will be better understood from the
following detailed descriptions of the preferred embodiments
according to the present invention, taken in con junction with the
accompanying drawings, in which FIG. 1 is the flow view showing the
first preferred embodiment according to the present invention;
[0007] FIG. 2 is the view showing the n-side up semiconductor of
the first preferred embodiment;
[0008] FIG. 3 is the view showing the first preferred embodiment
having the n-side up structure;
[0009] FIG. 4 is the view showing the first preferred embodiment
having the p-side up structure;
[0010] FIG. 5 is the flow view showing the second preferred
embodiment;
[0011] FIG. 6 is the view showing the n-side up semiconductor of
the second preferred embodiment;
[0012] FIG. 7 is the view showing the resistance-varied transparent
conducting layer adhered on the n-side up semiconductor of the
second preferred embodiment;
[0013] FIG. 8 is the view showing the n-side up second preferred
embodiment;
[0014] FIG. 9 is the view showing the metal layer adhered on the
resistance-varied transparent conducting layer of the second
preferred embodiment;
[0015] FIG. 10 is the flow view showing the third preferred
embodiment;
[0016] FIG. 11 is the view showing the n-side up semiconductor of
the third preferred embodiment;
[0017] FIG. 12 is the view showing the n-side up third preferred
embodiment;
[0018] FIG. 13 is the view showing the resistance-varied
transparent conducting layer with a uniform overall thickness; a n
d
[0019] FIG. 14 is the view showing the resistance-varied
transparent conducting layer with a non-uniform overall
thickness.
DESCRIPTIONS OF THE PREFERRED EMBODIMENTS
[0020] The following descriptions of the preferred embodiments are
provided to understand the features and the structures of the
present invention.
[0021] Please refer to FIG. 1 to FIG. 4, which are a flow view of a
first preferred embodiment; a view showing an n-side up
semiconductor of the first preferred embodiment; and views showing
the first preferred embodiment having an n-side up structure or a
p-side up structure according to the present invention. As shown in
FIG. 1, the present invention is a method of a uniform current
distribution using a current modified layer, comprising the
following steps:
[0022] (a) Obtaining a semiconductor with a p-n junction 11: As
shown in FIG. 2, a p-type semiconductor 21 and an n-type
semiconductor 22 are obtained through epitaxy growth and are bonded
to obtain a semiconductor with a p-n junction 23, where the
semiconductor with the p-n junction 23 has an n-side up structure
or a p-side up structure; the semiconductor with the p-n junction
23 has a structure of pairs of multiple-quantum-well (MQW) or a
structure of layers of heterostructures and p-type-intrinsic-n-type
(p-i-n optical detector structures; and the semiconductor with the
p-n junction 23 is made of at least one III-V material, which is
GaAs, InP, GaN, AlGaN, AlN, GaInN, AlGaInN, InN, GaInAsN or GaInPN,
or is made of a monocrystalline silicon, a multicrystalline silicon
or an amorphous silicon.
[0023] (b) Deposing a resistance-varied transparent conducting
layer 12: As shown in FIG. 3 and FIG. 4, a resistance-varied
transparent conducting layer 24 is then added on the semiconductor
with the p-n junction 23 to form a current modified layer (CML),
where the resistance-varied transparent conducting layer 24 is flat
and is transparent; resistance of the resistance-varied transparent
conducting layer 24 is decreased toward all directions from a point
on a bonding pad between the resistance-varied transparent
conducting layer 24 and the semiconductor with the p-n junction 23
and thus a current is effectively spread toward all directions as
well; the resistance-varied transparent conducting layer 24 is made
of a metal oxide; the resistance-varied transparent conducting
layer 24 is a p-type semiconductor, an n-type semiconductor or an
insulator; the resistance-varied transparent conducting layer 24 is
transparent to visible light, infrared (IR) and ultraviolet (U V);
the resistance-varied transparent conducting layer 24 is adhered to
the semiconductor with the p-n junction 23 above a p-type
semiconductor 21 of the semiconductor with the p-n junction 23,
beneath the p-type semiconductor 21 of the semiconductor with the
p-n junction 23, above an n-type semiconductor 22 of the
semiconductor with the p-n junction 23, or beneath the n-type
semiconductor 22 of the semiconductor with the p-n junction 23; and
the resistance-varied transparent conducting layer 24 has a uniform
overall thickness or a non-uniform overall thickness.
[0024] With the above steps, the present invention is applied to an
electric device, which is a light emitting display (LED), a solar
cell, an organic LED (OLED), a liquid crystal display (LCD) or a
touch panel. With a coordination of the CML formed by the
resistance-varied transparent conducting layer 24, a current in the
electric device is uniformly distributed and thus the effectiveness
of the electric device is improved.
[0025] Please refer to FIG. 5 to FIG. 9, which are a flow view of a
second preferred embodiment; a view showing an. n-side up
semiconductor of the second preferred embodiment; a view showing a
resistance-varied transparent conducting layer adhered on the
n-side up semiconductor of the second preferred embodiment; a view
showing an n-side up second preferred embodiment; and a view
showing a metal layer adhered on the resistance-varied transparent
conducting layer of the second preferred embodiment. As shown in
FIG. 5, the present invention is a method of a uniform current
distribution using a current modified layer, comprising the
following steps:
[0026] (a) Obtaining a semiconductor with a p-n junction 31: As
shown in FIG. 6, a p-type semiconductor 41 and an n-type
semiconductor 42 are obtained through epitaxy growth and are bonded
to obtain a semiconductor with a p-n junction 43, where the
semiconductor with the p-n junction 43 has an n-side up structure
or a p-side up structure; the semiconductor with the p-n junction
43 has a structure of pairs of MQW or a structure of layers of
heterostructures and p-i-n optical detector structures; and the
semiconductor with the p-n junction 43 is made of at least one
III-V material, which is GaAs, InP, GaN, AlGaN, AlN, GaInN,
AlGaInN, InN, GaInAsN or GaInPN, or is made of a monocrystalline
silicon, a multicrystalline silicon or an amorphous silicon.
[0027] (b) Deposing a resistance-varied transparent conducting
layer 32: As shown in FIG.7, a resistance-varied transparent
conducting layer 44 is added on the semiconductor with the p-n
junction 43 to form a CML, where the resistance-varied transparent
conducting layer 44 is flat and is transparent; resistance of the
resistance-varied transparent conducting layer 44 is decreased
toward all directions from a point on a bonding pad between the
resistance-varied transparent conducting layer 44 and the
semiconductor with the p-n junction 43 and thus a current is
effectively spread toward all directions as well; the
resistance-varied transparent conducting layer 44 is made of a
metal oxide; the resistance-varied transparent conducting layer 44
is a p-type semiconductor, an n-type semiconductor or an insulator;
the resistance-varied transparent conducting layer 44 is
transparent to visible light, IR and UV; the resistance-varied
transparent conducting layer 44 is adhered to the semiconductor
with the p-n junction 43 above a p-type semiconductor 41 of the
semiconductor with the p-n junction 43, beneath the p-type
semiconductor 41 of the semiconductor with the p-n junction 43,
above an n-type semiconductor 42 of the semiconductor with the p-n
junction 43, or beneath the n-type semiconductor 42 of the
semiconductor with the p-n junction 43; and the resistance-varied
transparent conducting layer 44 has a uniform overall thickness or
a non-uniform overall thickness.
[0028] (c) Deposing a metal layer or resistance layer with a
non-uniform density 33: As shown in FIG. 8, a metal layer or
resistance layer 45 with a non-uniform density is added on the
resistance-varied transparent conducting layer 44 to form a CML.
With the non-uniform density of the metal layer or resistance layer
45, a current is flowed from a high-density position to a
low-density position, where the metal layer is a p-type
semiconductor or an n-type semiconductor; and the resistance layer
is a p-type semiconductor, an n-type semiconductor or a
nonconductor.
[0029] With the above steps, the present invention is applied to an
electric device, which is a LED, a solar cell, an OLED, a LCD or a
touch panel. With a coordination of the CML formed by the
resistance-varied transparent conducting layer 44 and the metal
layer or resistance layer 45, a current in the electric device is
uniformly distributed and thus the effectiveness of the electric
device is improved.
[0030] Please refer to FIG. 10 to FIG. 12, which are a flow view
showing the third preferred embodiment; a view showing the n-side
up semiconductor of the third preferred embodiment; and a view
showing an n-side up third preferred embodiment. As shown in FIG.
10, the present invention is a method of a uniform current
distribution using a current modified layer, comprising the
following steps:
[0031] (a) Obtaining a semiconductor with a p-n junction 51: As
shown in FIG.11, a p-type semiconductor 61 and an n-type
semiconductor 62 are obtained through epitaxy growth and are bonded
to obtain a semiconductor with a p-n junction 63, where the
semiconductor with the p-n junction 63 has an n-side up structure
or a p-side up structure; the semiconductor with the p-n junction
63 has a structure of pairs of MQW or a structure of layers of
heterostructures and p-i-n optical detector structures; and the
semiconductor with the p-n junction 63 is made of at least one
III-V material, which is GaAs, InP, GaN, AlGaN, AlN, GaInN,
AlGaInN, InN, GaInAsN or GaInPN, or is made of a monocrystalline
silicon, a multicrystalline silicon or an amorphous silicon.
[0032] (b) Deposing a resistance-varied transparent conducting
layer to be roughened 52: As shown in FIG. 12, a resistance-varied
transparent conducting layer 64 is added on the semiconductor with
the p-n junction 63 to form a CML; and then the resistance-varied
transparent conducting layer 64 is roughened on surface to form a
CML, where the resistance-varied transparent conducting layer 64 is
flat and is transparent; the resistance-varied transparent
conducting layer 64 is made of a metal oxide; the resistance-varied
transparent conducting layer 64 is a p-type semiconductor, an
n-type semiconductor or an insulator; the resistance-varied
transparent conducting layer 64 is transparent to visible light, IR
and UV; the resistance-varied transparent conducting layer 64 is
adhered to the semiconductor with the p-n junction 63 above a
p-type semiconductor 61 of the semiconductor with the p-n junction
63, beneath the p-type semiconductor 61 of the semiconductor with
the p-n junction 63, above an n-type semiconductor 62 of the
semiconductor with the p-n junction 63, or beneath the n-type
semiconductor 62 of the semiconductor with the p-n junction 63; and
the resistance-varied transparent conducting layer 64 has a uniform
overall thickness or a non-uniform overall thickness.
[0033] With the above steps, the present invention is applied to an
electric device, which is a LED, a solar cell, an OLED, a LCD or a
touch panel. With a coordination of the CML formed by the
resistance-varied transparent conducting layer 64, a current in the
electric device is uniformly distributed and thus the effectiveness
of the electric device is improved.
[0034] Please refer to FIG. 13 and FIG. 14, which are views showing
a resistance-varied transparent conducting layer with a uniform
overall thickness and a resistance-varied transparent conducting
layer with a non-uniform overall thickness. As shown in the
figures, a resistance-varied transparent conducting layer with a
uniform overall thickness 71 has a variable resistance in a
horizontal direction, where the resistance-varied transparent
conducting layer with a uniform overall thickness 71 has a variable
resistance coefficient (.rho.(x) having a correlation to a
horizontal position (x) on the resistance-varied transparent
conducting layer with the uniform overall thickness 71. The
resistance-varied transparent conducting layer with a non-uniform
overall thickness 72 has a resistance affected by the non-uniform
overall thickness, where a thickness at a position on the
transparent conducting layer (t(x)) and a variable resistance
coefficient (.rho.(x)) have a correlation to a horizontal position
(x) on the resistance-varied transparent conducting layer with the
non-uniform overall thickness 72; and the position on the
transparent conducting layer and the variable resistance
coefficient are obtained from a function, which can be a
discontinuous function.
[0035] To sum up, the present invention is a method of a uniform
current distribution using a current modified layer, where a
current is spread horizontally to solve the problem of
non-uniformly distributed current in a thin GaN LED.
[0036] The preferred embodiments herein disclosed are not intended
to unnecessarily limit the scope of the invention. Therefore,
simple modifications or variations belonging to the equivalent of
the scope of the claims and the instructions disclosed herein for a
patent are all within the scope of the present invention.
* * * * *