Microsoft Word - .doc StudentChi-Ting Wu
AdvisorYewChung Sermon Wu


College of Engineering
for the Degree of

i
Auger Ti/Pt/Au In
Ag Ag
Ni
Ni Ag 90%
GaN 470nm 90~100%
ii
StudentChi-Ting Wu AdvisorDr. YewChung Sermon Wu
Department of Material Science and Engineering
National Chiao-Tung University
In this thesis, the AlGaInP epi layer was transferred successfully
from GaAs to SiC substrate by wafer bonding technology at first. Then
the light-extraction efficiency was also increased by surface roughening
and new metal reflector.
The results of the experiments showed that the saturation current
of SiC-light emitting diodes (LEDs) was increased. Therefore, the issue
of joule-heat effect was solved by using SiC substrates instead of GaAs
substrates, because of the better heat conduction SiC substrates have.
The improvement of the light-extraction efficiency was due to the
surface roughening and new metal reflector. As the light driven by
multi-quantum well passed through the boundary of air and LEDs, the
rougher surface can decreased the probability of the total reflection.
Therefore, the light-extraction efficiency was improved.
Because of the high reflectivity, the Ag metal was chosen to
replace the BeAu alloy for reflector in the next experiments. The results
of experiments also showed that the light intensity of LEDs was
enhanced by using Ag reflector. The light intensity of SiC-LEDs with
iii
Ag reflector and surface roughening was 4 times than that of general
GaAs-LEDs at the injection current of 20mA.
However, there are still some issues for using Ag reflector. The
advance analyses showed that heating process might cause the
agglomeration of Ag reflector and the diffusion of indium atoms. These
phenomenons decreased the reflectivity of the Ag reflector. Therefore,
the diffusion barrier layer (Ti/Pt/Au) and Ni thin film were used in the
structure of LEDs to solve these issues. Finally, the reflectivity of the
Ag reflector was enhanced as high as ~90% by means of the new
scheme, even after annealing at 270 for 1 hour.
iv






vi

3.2 Ag ............................ 37
3.3 Sapphire u-GaN Ni/Ag ........ 39

4.2.2 Auger - ............. 59
4.2.3 .................... 62
4.2.4NiO ............................... 67
..................................... 69
1-3(B) LED OM ................. 6
1-4 AlInGaP LED/ITO/Cu 500°C/30 min Auger
depth profiles .......................... 6
1-5 GaAs sub. Cu sub. I-V ............ 7
2-1 ............ 14
2-3 .............. 16
2-6 .......................... 21
2-8 SiC Sapphire ATON
τ ........................... 27
2-10 ................... 28
2-11 ................... 29
2-12 ....... 29
2-13 ............... 30
(b) Transparent metal layer
....................................... 30
2-16 ......... 31
2-17 ......................... 32
3-2 .......................... 35
3-4(A) Glass/ITO/Ni/Ag ................... 37
3-4(B) Glass/ITO/Ag/Ni ..................... 38
3-4(C) Glass/ITO/Ni/Ag/Ni .................. 38
3-5 Glass/u-GaN/ITO/Ni/Ag ............... 39
4-1(A) ........... 41
4-2 SiC 20mA
........................................ 42
4-4
4-7
xi
4-10(A)Ag TEM Cross Section ........ 52
4-10(B)Ag 330 o C TEM Cross Section .... 53
4-10(C)Ag 530 o C TEM Cross Section .... 53
4-11(b)Ag ........................... 54
4-11(e)AgAl ......................... 55
4-11(g)Ag AgAl ......... 55
4-12(A)AgCu Ag Cross
Section................................... 56
4-12(B)AgCu Ag SIMS ........ 56
4-13(A) ITO/Ag/Ni RTA 200 o C 1
................................ 57
4-13(B) ITO/Ni/Ag RTA 200 o C 1
................................ 57
xii
1 ............................ 57
4-14(A) ITO/Ag/Ni RTA 200 o C 1
................................ 58
4-14(B) ITO/Ni/Ag RTA 200 o C 1
................................ 58
1 ............................ 58
4-15(B) ITO/Ni/Ag
4-15(C) ITO/Ni/Ag/Ni
4-16(C) ITO/Ni/Ag/Ni Auger
...................................... 62
xiii
....................................... 63
................................... 64
................................... 64
............................... 64
......................................... 65
......................................... 65
......................................... 65
4-20(B)ITO/Ni/Ag Rms=16.51nm ..... 66
4-21 Ni Glass Sapphire
....................................... 67
xiv
...................................... 68
4-23 Sapphire u-GaN RTA 200 o C
Ni/Ag .......... 69
Auger ............................ 70
Auger ............................ 71
Auger .......................... 72




2002

2
(Lattice match)
,(DH,Double Hererojuction)
(Active Layer) GaAs
LED
LED GaAs
LED LED P-type
(Current Spreading) P-AlGaInP

(3) AlGaInP (Sheet Resistance)

GaP [23] GaP P-type
GaP
LED AlGaInP LED LED
defect)
GaP
(a) (b)
ITO 90%
ITO AlGaInP GaInP
GaAs
GaAs
1.2

1-4

SiCSiC(490W/m-K)
CuWafer BondingSiC
6
1-4 AlInGaP LED/ITO/Cu500°C/30 minAuger depth
profiles[4]
1-5 GaAs sub. Cu sub. I-V [4]

2.1


SOI-
optoelectronic integration circuits
MMICsmonolithic microwave integrated circuits
2.1.1
[5]
1. lattice mismatch
dislocationdefect

2.1.2

Intermediate layer
wafer bonding[6]



2.




Spin on glass SOG BCB
Bzocyclobutene
tw tw Ri.e.2tw < R
R [1011]
(100) ν = 0.29 4 525 μm
1μm
0.5 cm 2-1



2-2 Z. L. Liau D. E. Mull
1990

-6 /°C
Mo5.27×10 -6 /°C
Stainless Steel16×10 -6 /°C


2-2 Z. L. Liau D. E. Mull [9]
16
LED
2-4

GaAs

19
III-V
(GaN)GaN 3.5eVInN 1.89eVAlN 6.28eV
2.0eV 6.3eV


20
[14]GaAs

LED

2.3.2


(ITOIZO...)
2.4
p-n p-n

(excess minority carries)
(spontaneous emission)

90% 10~20%
23
16 o =(1/4ns
2 )x4π 2%

24

17
efficiency
ηinj
Cao 18 J. Song19ηrad


1Critical Angle
Schad 20
SapphirenSap1.785 SiCnSiC2.7
τ 2-7 τ
64° 2-8 2-9
(1) 64°
GaN ATON 25%
52%

1.62-12
I. Schnitzer
9% 30% C. Huh T. Fujii23
2-14
AgPtAl 2-16

2-8 SiC Sapphire ATON τ
[20]
2-10 [21]
Transparent metal layer [23]
31
2-16 [25]
2. Joule-heat effect

32
R. H. Horng 28-29 S. J. Wang
31 2-1
AlPtAg

MOCVD(Metal-Organic Chemical Vapor Deposition) GaAs
AlGaInP p-AlGaInP ITO 300nm
Mesa Pad n-pad p-pad
AlGaInP 3-1
LEDs 3-2
p-AlGaInP ITO 300nm
34
(BeAu Ag) Ti/Pt/Au SiC Ti/Au/In
Au-In 250 o C 1hr NH4OHH2O2=110
GaAs n-AlGaInP HClH3PO4=12
InGaP (etching stop layer)GeAe300 o C
10 dot KIH2O=15 GeAu dot
n-AlGaInP (Surface Roughening) HCl
H3PO4H2O=1202 ITO 300nm Mesa
ICP Pad n-pad p-pad
LED 3-3

LED Deposition GaAs GaAs
GaAs LED
N-pad
37
3.2 Ag
(Glass)(Sapphire) ITO Ag
mirror ITO Ag Ni RTA

3-4(A) Glass/ITO/Ni/Ag
Reflectivity
38
3-4(B) Glass/ITO/Ag/Ni
3-4(C) Glass/ITO/Ni/Ag/Ni
GaN
10
HClH3PO4H2O=1202
0 5 10 AFM ( 4-1)
(Rms)
9.37nm(MQW)
0.491.819.37(nm)
2.2V
4-2 SiC
4-2 SiC 20mA
4.1.3
0
20
40
60
80
100
43
Ti/Pt/Au(630nm)
AlGaInP
Mirror
AlGaInP
100mA~150mA 20mA 50mcd BeAu
device BeAu Roughening device
450~500mA GaAs 3.3 20mA BeAu
device 205mcdBeAu Roughening device
240mcd GaAs 76~80% surface
Roughening 15%
GaAs substrate LED structure

Ag mirror 4-5 BeAu Ag
Hitachi U300
(630nm)Ag
100%( Al ) BeAu 630nm 88%
Ag(470nm)100%AgBeAu
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
46
,
,(Diffusion Barrier Layer)
device (Ti/Pt/Au) BeAu Roughening device
4-7(Ti/Pt/Au)
30
40
50
60
70
80
90
100
110
R
(Ti/Pt/Au)BeAu Roughening device (Ti/Pt/Au) 20mA
259mcd
Ag device BeAu Ag Roughening device (Ti/Pt/Au)
20mA 270mcd BeAu Roughening device
(Ti/Pt/Au) 5% Ag BeAu

SiC substrate In
ITO
P-pad
Ti/Pt/Au
N-pad
48

InAu
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
49

In Ag
In 4-9(C)
Ti/Pt/Au ITO In
400sec Ag 400sec
900sec In
(Ti/Pt/Au) In 4-7
In
(A)
0 500 1000 1500 2000 0
50000 100000 150000 200000 250000 300000 350000 400000 450000 500000 550000
A re
a (C
PS *e
0 50000
100000 150000 200000 250000 300000 350000 400000 450000 500000 550000
A re
a( C
PS *e
0
20
40
60
80
100
470nm Ag
June-O Song[30] Ag
330~530 o C Ag
4-10(A)(B)(C)Ja-Yeon Kim[31] Ag 500 o C
AgAl
4-11(b)(c)(e)(f)(g) AgAl 500 o C
85% 4-12 Hyunsoo Kim[32]
AgCu Ag AgCu Cu
Ag 400 o C 470nm
86% 4-12(A) SIMS
Cu CuO AgO 4-12(B)
4-10(A) Ag TEM Cross Section[30]
53
4-10(B) Ag 330 o C TEM Cross Section[30]
4-10(C) Ag 530 o C TEM Cross Section[30]
4-11(b) Ag (c) Ag 500 o C 1min
[31]
54
4-11(e) AgAl (f) AgAl 500 o C 1min
[31]
55
56
ITO Ag
ITO AgO
Hyunsoo Kim[34] AgCu
Ag AgCu Cu Ag
400 o C 470nm 86%
ITO Ag barrier
layer Ni Ni NiO NiO
Ag Ni barrier
Ag AgO
(A)ITO/Ag/Ni(B)ITO/Ni/Ag(C)ITO/Ni/Ag/Ni
RTA 200 o C - 1 470nm
90~100%( Al ) ITO/Ni/Ag
ITO/Ni/Ag/Ni ITO/Ag/Ni 200
o C ITO O Ag AgO
Ni NiO
57
70
80
90
100
110
120
130
R
4-14 (A)ITO/Ag/Ni
470nm 70~90%( Al)
ITO/Ni/Ag ITO/Ni/Ag/Ni ITO/Ag/Ni
270 o C ITO O Ag 200
o C
58
NiO 85~90% ITO/Ag/Ni 70%
4-14 (A)ITO/Ag/Ni (B)ITO/Ni/Ag

(C)ITO/Ni/Ag/Ni 200 o C - 1
ITO/Ni/Ag ITO/Ag/Ni 470nm 65%
RTA 200 270 o C
Ag AgO
400 450 500 550 600 650 700
30
40
50
60
70
80
90
100
110
120
130
R
470nm 80%
4-15 (A)ITO/Ag/Ni (B)ITO/Ni/Ag
4.2.2 Auger -
Ni ITO O Ag AgO
Auger Ni NiO 4-16(A)
Glass/ITO/Ag/Ni 0~200sec Ni
400 450 500 550 600 650 700
30
40
50
60
70
80
90
100
110
120
130
Ag O 800sec Ag ITO
Ag O Ag AgO AgO
4-16 (A) ITO/Ag/Ni Auger
4-16(B) Glass/ITO/Ni/Ag
0~1000secAgO1000sec
Ni O NiO ITO Ni
O O NiO Ag AgO
ITO/Ni/Ag
0
100000
200000
300000
400000
500000
600000
700000
800000
4-16(C) Glass/ITO/Ni/Ag/Ni
0~200sec Ni O NiO
200~600sec Ag O Ni 600sec
NiO ITO/Ni/Ag/Ni Ni
Ag Ag
0 200 400 600 800 1000 1200 1400
0
100000
200000
300000
400000
500000
600000
700000
800000
4.2.3
ITO/Ni/Ag/Ni RTA SEM 4-17(A) Ni
4-17(B) Ag Ag AgO
4-17(A)(C) Ni
4-18(A)(B)(C) ITO/Ag/NiITO/Ni/Ag
ITO/Ni/Ag/Ni 4-18(B) Ag
4-17(B) Ag RTA
0 200 400 600 800 1000 1200 1400
0
100000
200000
300000
400000
500000
600000
700000
800000

SEM
4-18 (A)ITO/Ag/Ni(B)ITO/Ni/Ag(C) ITO/Ni/Ag/Ni 200 o C
SEM
RTA FIB Cross Section 14-9(A) Ag
ITO 4-19(B) Ag
4-19(C) Ni Ag
4-19 (A)ITO/Ag/Ni(B)ITO/Ni/Ag(C) ITO/Ni/Ag/Ni RTA200 o C
FIB Cross Section
(C)
(B)
(A)
200oC Ag 4-20(A) RTA
Glass/ITO/Ni/Ag 4-20(B) Glass/ITO/Ni/Ag AFM
RTA Rms=7.54nm
Rms=16.51nm 2.2
Ag RTA N2
4-20 (A)ITO/Ni/Ag RTA Rms=7.54nm (B)ITO/Ni/Ag
Rms=16.51nm
NiO
Ni 200~550 o C Ni NiO 4-21
Ni
470nm Glass/Ni 75% 200 270 o C
Glass/NiO 470nm 80%
4-22200 o C550
o C1200
550 o C
4-21 Ni Glass Sapphire
400 450 500 550 600 650 700 50
60
70
80
90
100
68
4.2.5 Sapphire GaN Mirror
Sapphire u-GaN u-GaN
ITO/Ag/Ni barrier layer
Ni/Ag GaN 4-23
RTA 200 o C ITO/Ag/Ni 470nm
70%ITO/Ni/Ag ITO/Ni/Ag/Ni 90~100%(
Al ) ITO/Ni/Ag
GaN
60
70
80
90
100
69
4-23 Sapphire u-GaN RTA 200 o C
Ni/Ag
4.2.6 Sapphire GaN Mirror Auger

Ni ITO O Ag AgO
Auger Sapphire u-GaN Ni
barrier NiO 4-24(A) Sapphire/u-GaN/ITO/Ag/Ni
0~200sec Ni O
NiO200~700secAgO500sec
Ag ITO Ag O Ag AgO
AgO
30
40
50
60
70
80
90
100
110
120
130
70
4-24(A) Sapphire u-GaN ITO/Ag/Ni Auger

0~6 00sec Ag O
600sec Ni O NiO
ITO Ni O O NiO Ag AgO
ITO/Ni/Ag
0
100000
200000
300000
400000
500000
600000
700000
800000
4-24(B) Sapphire u-GaN ITO/Ni/Ag Auger

0~100sec Ni O NiO
150~600sec Ag O Ni 600sec
NiO ITO/Ni/Ag/Ni Ni
Ag Ag
0 200 400 600 800
0
100000
200000
300000
400000
500000
600000
700000
800000
0
100000
200000
300000
400000
500000
600000
700000
800000
4
BeAu mirror LED CV-LED( LED) 76%BeAu
-Roughening LED 80%BeAu-Roughening-TiPtAu LED
81%Ag-Roughening-TiPtAu LED
82%
4. RTA Ag

Sapphire u-GaN mirror 470nm 90%

74
1000~2000W/mK()

P-type Ohmic contact Mirror UV
90%
75

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