Table Of ContentCrystalline semiconductors in the form of thin films are crucial materials for many M
modern, advanced technologies in fields such as microelectronics, optoelectronics,
display technology, and photovoltaic technology. Crystalline semiconductors can be e
produced at surprisingly low temperatures (as low as 120 ˚C) by crystallization of t
amorphous semiconductors, which are put in contact with a metal. This so-called a
metal-induced crystallization process has attracted great scientific and technological l
-
interest because it allows the production of crystalline semiconductor–based I
advanced devices at very low temperatures, for example, directly on low-cost (but n
often heat-sensitive) substrates. d
u
This book provides the first comprehensive and in-depth overview of the current
c
fundamental understanding of the metal-induced crystallization process and further
e
elucidates how to employ this process in different technologies, for example, in thin-
d
film solar cells and display technologies. It aims to give the reader a comprehensive
perspective of the metal-induced crystallization process and thereby stimulate the
C
development of novel crystalline semiconductor–based technologies.
r
y
Zumin Wang obtained his PhD in condensed matter physics at the s
University of Science and Technology of China in 2005. He was a t
postdoctoral fellow (2005–2008) and since 2008 is a senior scientist a
in Department Mittemeijer at the Max Planck Institute for Intelligent l
l
Systems, Stuttgart, Germany. His work contributed pronouncedly i
z
to the achievement of fundamental understanding and advanced
applications of metal-induced crystallization. a
t
Lars P. H. Jeurgens obtained his PhD in materials sciences at i
o
the Delft University of Technology, Netherlands, in 2001. After a
n
postdoctoral period working for the Dutch Technology Foundation,
Netherlands, he moved to the Max Planck Institute for Intelligent
Systems in 2003 to lead a research group working on “reactions
and phase transformations at surfaces and interfaces” within
Department Mittemeijer. He joined the Swiss Federal Laboratories
W
for Materials Science and Technology, Switzerland, in 2012 and is
a
the head of the laboratory for “Joining Technologies and Corrosion.” n
g
|
Eric J. Mittemeijer was full professor of solid-state chemistry at J
e
the Delft University of Technology from 1985 to 1998. Since 1998, u
he is director at the Max Planck Institute for Intelligent Systems rg
and a full professor of materials science at the University of e
n
Stuttgart, Germany. He leads a research department in the field s
of phase transformations. He has co-authored more than 600 | M
scientific papers in international scientific journals and has received
i
numerous honors for his scientific work. tt
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m
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i
j
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r
V401
ISBN 978-981-4463-40-9
Metal-Induced
Crystallization
-
Pan Stanford Series on Renewable Energy — Volume 2
Metal-Induced
Crystallization
Fundamentals and Applications
editors
Preben Maegaard
edited by
Anna Krenz
Wolfgang Palz Zumin Wang
Lars P. H. Jeurgens
Eric J. Mittemeijer
The Rise of Modern Wind Energy
Wind Power
for the World
CRC Press
Taylor & Francis Group
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Contents
Preface
1. In troduc tion to Metal-Induced Crystallization x1i
Zumin Wang, Lars P. H. Jeurgens, and Eric J. Mittemeijer
1.1 A Brief History of Metal-Induced Crystallization 2
1.2 Experimental Methods for Investigating the
Metal-Induced Crystallization Process 6
1.2.1 X-Ray Diffraction 6
1.2.2 Transmission Electron Microscopy 7
1.2.3 Differential Scanning Calorimetry 8
1.2.4 Spectroscopic Ellipsometry 9
1.2.5 Other Techniques 9
1.3 Metal-Induced Crystallization Processes in
Crystalline Metal/Amorphous Semiconductor
Systems: An Overview 10
1.3.1 Amorphous Semiconductors
Showing MIC 10
1.3.2 Crystalline Metals Inducing MIC 11
1.3.3 Categories of Metal-Induced
Crystallization 12
1.3.3.1 Category A 15
1.3.3.2 Category B 15
1.3.4 Metal-Induced Crystallization
2. ThermodynamicMs eacnhda Antiosmmsic Mechanisms of 15
Metal-Induced Crystallization of Amorphous
Semiconductors at Low Temperatures 25
Zumin Wang, Lars P. H. Jeurgens, and
Eric J. Mittemeijer
2.1 Introduction 26
2.2 Metal-Induced Covalent Bond Weakening 28
2.3 Interface Thermodynamics of Metal-Induced
Crystallization 30
2.3.1 Grain Boundary Wetting 30
vi Contents
2.3.2 Nucleation of Crystalline
Semiconductors 36
2.3.3 Continued Crystallization and Layer
Exchange 44
2.4 Ultrathin Metal–Induced Crystallization:
Tailoring the Crystallization Temperature
of Amorphous Semiconductors 51
3. 2D.i5ff usionC,o Cnrcylustsailolinzas tiaonnd, Oanudtl oLoayke r Exchange upon 54
Low-Temperature Annealing of Amorphous
Si/Polycrystalline Al Layered Structures 61
Jiang Yong Wang, Zumin Wang, Lars P. H. Jeurgens,
and Eric J. Mittemeijer
3.1 Introduction 62
3.2 Diffusion in a-Si/c-Al Layered Structures
upon Low-Temperature Annealing 63
3.2.1 Methods for Determination of
Diffusion Coefficients by AES Depth
Profiling of Layered Structures 64
3.2.1.1 Method 1 64
3.2.1.2 Method 2 65
3.2.2 Application to a-Si/c-Al Bilayered and
Multilayered Structures 65
3.2.2.1 Multilayered structure
4× a-Si (15 nm)/c-Al (15 nm) 66
3.2.2.2 Bilayered structure of a-Si
(150 nm)/c-Al (50 nm) 69
3.2.3 Operating Diffusion Mechanism 71
3.3 Aluminum-Induced Crystallization of
Amorphous Si upon Low-Temperature-
Annealing of a-Si/c-Al Layered Structures 72
3.3.1 Experimental Observations of AIC 74
3.3.1.1 Multilayered structure
10× a-Si (50 nm)/c-Al (50 nm) 74
3.3.1.2 Bilayered structure a-Si
(150 nm)/c-Al (50 nm) 76
3.3.1.3 Direct visualization of
Al-induced crystallization
of a-Si 78
Contents vii
3.3.2 Thermodynamics of AIC of a-Si 80
3.3.2.1 Inward diffusion of Si along
Al GBs into the Al sublayer
(Al GB wetting) 81
3.3.2.2 Nucleation of crystalline Si
at Al grain boundaries 82
3.4 Aluminum-Induced Layer Exchange upon
Low-Temperature Annealing of a-Si/c-Al
Layered Structures 84
3.4.1 Experimental Observations of ALILE 84
3.4.1.1 Multilayered structure 4×
a-Si (15 nm)/c-Al (15 nm) 84
3.4.1.2 Bilayered structure a-Si
(150 nm)/c-Al (50 nm) 86
Æ
3.4.1.3 Direct visualization of
Al Si layer exchange 88
3.4.1.4 Microstructural changes of
the Al and Si phases upon
ALILE 89
3.4.2 Thermodynamics of ALILE 92
3.4.3 Mechanism of ALILE 98
4. 3M.5e tal-InMdauicne dC oCnryclsutasliloiznasti on by Homogeneous 101
Insertion of Metallic Species in Amorphous
Semiconductors 113
Antonio R. Zanatta and Fabio A. Ferri
4.1 Introduction 114
4.2 Sample Preparation and Characterization 116
4.3 Crystallization of Amorphous Si and Ge Films 122
4.4 Structural Disorder and Crystallization 125
5. 4A.l5u minuFmin-aInl dRuecmedar Ckrsy stallization: Applications in 131
Photovoltaic Technologies 137
Abdelilah Slaoui, Prathap Pathi, and Özge Tuzun
5.1 Introduction 138
5.2 Metal-Induced Crystallization of Amorphous
Silicon 141
5.3 Aluminum-Induced Crystallization 145
viii Contents
5.3.1 Solid Solubility of the Al/Si System 147
5.3.2 Diffusion of Silicon in Aluminum 148
5.3.3 Thermodynamics and Kinetics of
Al/Si Bilayers 150
5.3.4 Formation of AIC Layers 158
5.3.5 Effect of Growth Parameters on the
AIC Growth Kinetics and the
Resulting c-Si Microstructure 161
5.3.5.1 Effect of thermal budget
(temperature anxd time) 161
5.3.5.2 Effect of the interfacial
oxide layer (AlO ) 166
5.3.5.3 Effect of the aluminum layer 169
5.3.5.4 Al/Si thickness ratio 174
5.3.5.5 Effect of hydrogen in a-Si 175
5.3.5.6 Effect of substrate 177
5.4 Preferential (100) Crystal Orientation of
AIC Layers 180
5.5 Electrical Characteristics of AIC Poly-Si
Layers 182
5.6 Applications of AIC for Solar Cell Fabrication 182
5.6.1 Epitaxy and Its Characteristics 182
5.6.2 Solar Cell Results 186
6. 5A.p7p licatiSounmsm ofa rMye atnadl- ICnodnuccleuds iCornysst allization 188
Polycrystalline Silicon for Advanced Flat-Panel
Displays 199
Man Wong, Hoi Sing Kwok, Shuyun Zhao,
Zhiguo Meng, Pengfei Sun, Wei Zhou, and Tsz Kin Ho
6.1 Introduction 199
6.2 Pixel Circuits for AMLCDs and AMOLEDs 208
6.3 Driver-Integrated LCD Panels 210
6.4 MIC TFTs Applied to Field-Sequential Color
LCDs for Small-Size Panels 212
6.4.1 Introduction to Field-Sequential
Color LCDs 212
6.4.2 Design of the Active-Matrix Array 214
6.4.2.1 Working principle of the
FSC LCD 214
