Embed Size (px)
Citation preview
Materials Science in Electronics devices
- Semiconductor devices -
2014 Yutaka Oyama
http://www.material.tohoku.ac.jp/~denko/lab.html
Contents
・Material issue of semiconductor devices and fabrication
process
・Ultra fast and high frequency semiconductor electronic and
photonic devices
・Crystal growth and semiconductor device epitaxy
・Device grade evaluation of semiconductor crystals
Optical fiber network in Japan&Worldwide
Background: activities in Tohoku UniversitySemiconductor
laser (1957)
Light
source
Optical fiber
Graded Index fiber (1964)
Avalanche photodiode
Pin photodiode (1950)
propagation detection
Optical fiber network (NTT)
Oversea cable Total length
13200kmPacific
ocean
Fiber cable under the sea
(Kagoshima-Okinawa 1000km)
Fiber To The Home(FTTH)
Fiber network (domestic)
Multi-media new frontier
FTTH Fiber To The Home
No. of contract of FTTH service in Japan
20062005200420032002
104 contracts
DSL 【xDSL】Digital Subscriber Line
NO. of contract of DSL service
104 contracts
20062005200420032002
saturation
decreased
Radio spectrum300GHz
3KHz
IRVisible
light UVX-ray
Cosmic
ray
Gamma
ray
30THz
Frequency
Allocation
(USA)
LD/LEDHEMT
HBT
Sub
millimeter
Not used region
THz region
Our target device for not-used THz region
ISIT
TUNNETT
(Semiconductor Raman laser) -30THz
BPT
FET
MOS
Thyrister
IGBT
環境汚染物質プラズマ分解
電気自動車動力制御
-----frequency-----
NOT USED
THz REGION
ＩＳＩＴTUNNETT
RAMAN LASER
FAR INFRAREDLASER
SI THYRISTER
ULTRA FAST ＳＩ DIODE
TARGET DEVICESTODAY’S ISSUE
ＨＢＴ
，，，
LAB’S TARGET DEVICES
THz SOLID SOURCE
OUTPUT POWER vs FREQUENCY OF SEMICONDUCTOR
DEVICES
RF-SIT
Ou
tpu
t p
ow
er
(W)
Operation Frequency (Hz)
wavelength
NIR DFG
*NIR DFG: Near Infrared laser induced
Differential Frequency Generation
*ISIT: Ideal static induction transistor
*TUNNETT: Tunnel injection transit time effect diode
LASER
Light Amplification by Stimulated Emission of Radiation
light
Spontaneous
Emission
Stimulated
emission
Energy distribution of
electron
Fermi-Dirac distribution
Equilibrium⇔spontaneous熱平衡状態 自然放出
Negative temperature
distribution ⇔ stimulated（誘導放出）
（inversion） emission
From MASER (Microwave Amplification by Stimulated Emission of Radiation
Higher energy state
(excited state)
Lower energy state
light
Resonator
(cavity)
Resonator
(cavity)
負の温度
Laser is composed with
Laser material, a set of parallel mirror (cavity)
Methods to realize the inversion distribution （反転分布）
Flash lamp (solid laser etc.)
Electron injection（semiconductor laser: LD）Gas discharge（gas laser）LD excitation
Characteristic feature of laser
Coherent :interference due to well defined phase
Directional: parallel beam
Monochromatic light due to resonance
High energy density
tzAA 2
2cos0
Ln 2
Phase term
光通信三要素
光源 伝送路 検出器
半導体レーザ（半導体ﾚｰｻﾞ・ﾒｰｻﾞ：東北大）発光ダイオード
ｶﾞﾗｽファイバー（屈折率分布型ファイバー：東北大）プラスティックファイバー赤外線無線伝送
Ｐｉｎフォトダイオードｱﾊﾞﾗﾝｼｪ（雪崩）フォトダイオード（東北大）
変調
静電誘導トランジスタ
多重周波数分離・多重周波数検波
静電誘導トランジスタ半導体ラマンﾚｰｻﾞ
Three principle components for optical
communication
Light
source
Propagation
lineLight detector
Semiconductor laser(semiconductor maser:
Tohoku univ.)
Light emitting diode
Glass fiberGraded index fiber, (Tohoku univ.)
Step index fiber
Prastic fiber
IR transmission
RF transmission
pin photo diode (fast response)
Avalanche photo diode (high
sensitive amplification)
Tohoku Univ.
modulation
Static Induction
Transistor (Tohoku
Univ.)
Static Induction Transistor
Semiconductor Raman Laser
demodulation
ＩＳＩＴ実現のための要素技術 極微細構造電子デバイスの基盤技術
バリスティック伝導による走行時間
DS
chtransitqV
mlt
22
*
Transit time due to ballistic electron
transport
4nm channel length transistor
structure
Source/Drain
4nm
S/D 4nm Transistor for THz freq.
≤ 0.16 ps
ISIT(Ideal Static Induction Transistor)
invented in 1979 by J.Nishizawa
(J. Nishizawa, Proc. 1979 IEEE Int. Conf. Solid State Devices, 1979.)Washington DC
Ballistic electron transport
No scattering of electrons with lattices
Operation frequency (estimated)
Up to 800GHz (0.8THz)
Tunnel transport
Tk
VV
qTAJB
F
DSGS
FD
*0
2* exp
From Bethe theory (thermo ionic emission)
22*
3
4 Tkqm
hI
Bt
sF
Ballistic electron injection efficiency
Tk
ETk
h
wEmEE
ionicthermJ
tunnelJ
B
CBB
FBCF
SD
SD
exp2
3
2exp
22
*2
From Simmons theory,
WKB approximation
2
22
*
2ln
28
3
CF
B
B
CB
FB
tunnelEE
Tk
Tk
E
Em
hw
Tunnel injection
dominated condition
GaAs 25nm (RT)
90nm (77K)
Case: 0.855V
EF-EC=0.15eVCB E
Categories of semiconductor devices
Electron transport devices
Electronic devices
•Power devices
DC(direct current) electric transmission
Electric vehicle
Super express train (inverter control)
Thyristor, power diode, IGBT(Insulating gate bipolar transistor)
•Low power consumption devices
Mobile phones, pad
MOS(Metal Oxide Semiconductor) device
GaAs FET
•High frequency (RF) devices
Microwave telecommunication
High speed CPU
Satellite broadcast
Short channel MOS
HEMT, HBT device
NRD device
TUNNETT, ISIT
IMPATT, GUNN
光デバイス・半導体レーザ光通信（ファイバー通信），情報メディア ＤＶＤ，ＣＤ，ＭＯ ,printer
溶接ストライプレーザ量子井戸レーザ面発光レーザ量子カスケードレーザ（光～遠赤外・マイクロ波）パワーレーザ・ﾏﾙﾁｽﾄﾗｲﾌﾟレーザ（～数 100Ｗ）
・発光ダイオードｲﾝﾃﾞｨｹｰﾀｰ，照明用
・光演算
発光デバイス
受光デバイス
波長領域遠赤外（PbTe，量子カスケードレーザ）近赤外（InGaAs)
可視光（AlGaAs,InGaAlP)
青色（GaN,SiC,ZnSe）
紫外線（ダイヤモンド）
pin, avalanche diode
Quantum well / dot device
Opto devices
(optoelectronics)Light emission
Light detection
Semiconductor laser (LD)(laser diode:LD)
Optical telecommunication
DVD CD writer/pickup
Welding (high power)
Simple edge emitting LD(stripe LD)
Quantum well LD
Surface emitting LD
(vertical cavity LD)
Quantum cascade LD
Multi-stripe LD(high power)
Light emitting diode (LED)Indicator
Lighting, illumination
Pin, avalanche diode
Quantum well/dot detector
Wavelength
Far IR PbTe, QCLD(quantum cascade LD)
Near IR InGaAs …..
Visible AlGaAs, InGaAlP ……
Blue InGaN, SiC, ZnO
UV GaN, Diamond
半導体デバイスプロセス
設計（ＣＡＤｼﾐｭﾚｰﾀｰ）
プロセス インプロセスモニター 特性
信頼性再現性
設計へ
各種TEG(Test Element Group)
In-situ (その場）分析膜厚ﾓﾆﾀｰ組成・ﾄﾞｰﾋﾟﾝｸﾞﾓﾆﾀｰ
デバイスの微細化低温・低損傷ｾﾙﾌｱﾗｲﾝﾌﾟﾛｾｽ
開発費用・期間の低減
ﾊﾞｰﾝｲﾝ・ﾌｨｰﾙﾄﾞﾃｽﾄ加速試験
問題点の把握と克服技術の開発
高速・自動測定
Principle semiconductor device process flow
Device design By
CAD
Circuit/device
simulation
Device process In-process monitor characterization
Reproducibility
testDevice design
Reduction of cost/time
Reduction of device size
requires low temp. low
damage process
TEG(Test Element Group)
In-situ monitoring of process
Thickness/doping
High speed &
automated test
Find problems
Develop new
process
Burn-in & accelerated
Field testFrom m to nm
半導体デバイスプロセス要素技術
金属・半導体・絶縁体（セラミックス）
半導体デバイス構造
半導体ほとんどは単結晶材料
他にｱﾓﾙﾌｧｽ半導体有機半導体など
Principle device elements of
semiconductor devices
Device structures
Metal, Semiconductor, Insulator (Ceramics)
Semiconductor
Single crystal material
Others
Amorphous (TFT Tr. LCD driver)
Polycrystalline (solar cells)
Organic semiconductors
半導体デバイスは、「金属・半導体・セラミックス」を総合して形成。理想型静電誘導トランジスタのプロセス例
METAL
35A
HEAVY DOPING
DOPING EPITAXY 1019-1020cm-3
(SURFACE STOICHIOMETRY CONTROL)
LOW-T& SELECTIVE
MOLECULAR LAYER EPITAXY (MLE)
WITH ATOMIC ACCURACY (AA)
HIGH QUALITY
REGROWN INTERFACE（SURFACE STOICHIOMETRY CONTROL）
LOW c CONTACT（METAL/SEMI CONTACT）NON-ALLOYED
VERY THIN MIXED LAYER
SELECTIVE EPITAXY
（SELF-ALIGN PROCESS）
ULTRA SHALLOW GROVE
LOW-T&DAMAGE ETCHING（PHOTO-STIMULATED GAS FLOW ETCHING）
LOW-T&DAMAGE SiN CVD
（REMOTE PLASMA CVD)
MISゲート｛
DETAILED CRITICAL PROCESSES FOR ISITMETAL/CERAMICS/SEMICONDUCTOR BREAKTHROUGH PROCESSES
S/D=3.5nm
Principle of MLE :GaAs case
Molecular Layer Epitaxy in brief
ALE(Atomic Layer Epitaxy) of poly-ZnS on glass substrate for EL application
T. Suntola, U.S. Patent 4058430, 1977.
M. Ahonen, M. Pessa, T. Suntola, Thin Solid Films 65 (1980) 301.
MLE(Molecular Layer Epitaxy) of GaAs single crystal on GaAs
J. Nishizawa et. al. Extended Abstracts of the 16th Conference on Solid State Device and Materials
(The Japan Society of Applied Physics, Kobe, Japan, 1984), p. 1.
J. Nishizawa, et. al. J. Electrochem. Soc., 132 (1985) 1197.
Molecular layer epitaxy of GaAs
Thin Solid Films, 225 (1993), 1-6.
Jun-ichi Nishizawa, Hiroshi Sakuraba Yutaka Oyama など
Principle of MLE
Mono-molecular layer epitaxy
Self-limiting epitaxy with atomic accuracy (AA)
Area selective epitaxy
表面反応Surface reaction process
Detailed reaction processes of Epitaxial growth
・Si_react
Vapor phase or solution reaction
Diffusion to the surface
Surface adsorption
Surface reaction
Surface diffusion
（migration）nucleation
desorption
Real surface reaction
process in MLE Si
Impurity doping: control of surface stoichiometry
Electrical activation of Te and Se in GaAs at extremely heavy doping up to 5×1020cm-3 prepared by
intermittent injection of TEG/AsH3 in ultra-high vacuum,
Journal of Crystal Growth, Volume 212, Issues 3-4, May 2000, Pages 402-410
Yutaka Oyama, Jun-ichi Nishizawa, Kohichi Seo and Ken Suto など Ohno T et. al.
0
0.5
1
1.5
2
2.5
DEZn Pressure (Torr)
Car
rier
Co
nce
ntr
atio
n (
cm-3
)
Gro
wth
Rat
e (A
/C
ycl
e)
AA Mode(C.C.)
AA'Mode(C.C.)
IG Mode(C.C.)
10
10
10
10
20
19
19
18
1x
5x
1x
5x
10 10 10 10-6 -5 -5 -4
3x 1x 3x 1x
Hole concentration vs. DEZn pressure for Zn doping for temperature synchronized MLE.
Zinc doping of GaAs grown with temperature synchronized molecular layer epitaxy
AsH3 AsH3DEZn TEG
evacuation evacuation evacuation evacuation
time
Tem
per
ature
temperature synchronized molecular layer epitaxy
AA' - after arsine doping mode
precursor injection phases
360 380 400 420 440 4600
1
2
4
AA Mode
AA'Mode
IG Mode
undoped
10
10
10
17
18
19
2x
1x
1x
3
Substrate temperature during AsH3 injection [・C]
Ho
le c
on
centr
atio
n
[cm
-3]
Gro
wth
rat
e per
cycl
e [
・]
Growth rate and hole concentration vs. temperature during arsine injectionfor Zn doped GaAs grown with temperature synchronized MLE.
file: d:\0q\fig_s56s.cdr ZnTS.cdr
DOPING CHARACTERISTICS OF p-GaAs:Zn MLE
Doping mode dependences of impurity concentration evaluated by one-epitaxial run: base DETe doping.
Extremely high and steep impurity profile
▲Ｔｅ DOPING
○Ｓｅ DOPING
UP TO 1021cm-3 IMPURITY CONCENTRATION
5x1019cm-3 ELECTRON CONCENTRATION
Required for nm-channel Tr.
DOPING CHARACTERISTICS OF n-GaAs MLE
DOPING CHARACTERISTICS OF p-GaAs:Be MLE
0 10 20 30 40 50 601018
1019
1020
1021
Be
co
nce
ntr
atio
n (c
m-3
)
Be(MeCp)2 injection time (sec)
●AA ■AG
UP TO 4x1020cm-3 IMPURITY CONCENTRATION
8x1019cm-3 HOLE CONCENTRATION
Required for nm-channel Tr.
Ohno T et. al.
Ultra low c metal/semiconductor contact:
non-alloyed and selective CVD by W(CO)6
XTEM of MS interface with atomically
flat interface
Low-resistance Contacts with Chemical Vapor Deposited Tungsten on GaAs Grown by
Molecular Layer Epitaxy
[J. Electrochem. Soc., 146 (1), (1999), 131 - 136]
Yutaka Oyama, Piotr Plotka, Fumio Matsumoto, Toru Kurabayashi, H.hamano,
Hideyuki Kikuchi and Jun-ichi Nishizawa など
Contact resistivity for n-GaAs (MLE grown)
Also for p-GaAs (down to 10-8Wcm2 order)
Almost the limit of TLM method
High quality regrown interface
"Optimization of low temperature surface treatment of GaAs crystal",
J.Nishizawa, Y.Oyama, P.Plotka and H.Sakuraba,
Surface Science, 348, 105-114 (1996). など
Good interface
No trace of oxides and carbide after optimized
surface treatment
QMS desorption analysis
Also by XPS analysis
High quality regrown interface: chemical analysis
[110]
[11
0]
{001}
R
F
R
R
R
F
F
F
F
FF
F
R
R
R
R
F
F
F
F
F
F
F
F
TOP VIEW
Regrown p+-GaAs:Be 1st n+-GaAs:Te&S
epitaxy (49nm)
1st n+-GaAs:Te&S
epitaxy (49nm)
S.I.GaAs
Ti/Au non-alloyed
contact
Sidewall tunnel junctions
(regrowth interface)
Sidewall tunnel junction
(regrowth interface)
CROSS SECTIONAL VIEW
RF F
Figure 1. Schematic drawings of the cross sectional and top view of the fabricated sidewall
tunnel diodes. “F” and “R” mean the first epitaxial layers and the regrowth layers. The
arrows indicate the positions of sidewall regrown tunnel junctions. Large pad has 100m
in length, and small one has 50m.
Application of MLE GaAs to high quality
ultra-small tunnel junctions
Side-wall regrowth process
Application of low-temperature area-selective regrowth for ultrashallow sidewall GaAs tunnel junctions
Yutaka Oyama, Takeo Ohno, Kenji Tezuka, Ken Suto and Jun-ichi Nishizawa
Applied Physics Letters, 81, 2563-2565 (2002). など
Ti/Au
non-alloyed
contact
n+-GaAs:Te&S layer
(50nm)regrown p+-GaAs:Be layer
SI GaAs substrate
sidewall
tunnel junction (SJ~10-8cm2)
100 nm
1 m
n+-GaAs:Te&S
p+-GaAs:Be
Application of MLE GaAs
to high quality ultra-small
tunnel junctions
Side-wall regrowth process
Figure 2. J-V
characteristics of GaAs
sidewall tunnel junctions at
290 and 77K on (a) normal
mesa, (b) 45° inclined
configuration and (c)
reverse mesa sidewall
orientations.
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.70.0
5.0x103
1.0x104
1.5x104
2.0x104
2.5x104
3.0x104
3.5x104
290K
77K
NORMAL MESA ORIENTATION
Curr
ent
Den
sity
[A
cm-2]
Voltage Bias [volts]
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.70.0
5.0x103
1.0x104
290K
77K
45° INCLINED
CONFIGURATION
Curr
ent
Den
sity
[A
cm-2]
Voltage bias [volts]
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
1x103
2x103
3x103
4x103
5x103
290K
77KREVERSE MESA
ORIENTATION
Curr
ent
Den
sity
[A
cm-2]
Voltage Bias [volts]
Record high peak current density
Current-voltage characteristics of sidewall TUNNEL junctions
Sidewall mesa orientation dependences
Ohno T et. al.
(Jin, 2003)
● Our results:2002
GaAs tunnel diode (PVCR=28)
(Ahmed, 1997)
Figure of merits of fabricated TUNNEL junctions
RITD:
Resonant Interband Tunnel diode Ohno T et. al.
0 200 400 600 800 1000 1200 1400
1018
1019
1020
tunnel junction
(regrown p+-GaAs:Be/n
+-GaAs:Te&S interface)
epitaxial/substrate
interface
Be
S
Te
Impuri
ty c
oncentr
ati
on [
cm-3]
Depth from the surface [A]
Very high & steep impurity profile at tunnel junction interface
up to 2x1018cm-3 impurities /A Ohno T et. al.
Ultra fast and high frequency semiconductor electronic
and photonic devices
To be continued to next week
