Oxide Thin Film Transistors book presents a comprehensive overview of oxide thin film transistor (TFT) science and technology, including fundamental material properties, device operation principles, modeling, fabrication processes, and applications.
Split into four sections, the book first details oxide TFT materials including material parameters, and electrical and contact properties. The next section describes oxide TFT devices including designs, reliability, and comparison with other TFT types. The third part delves into the fabrication processes of oxide TFTs. The last section provides insight into existing and emerging applications of oxide TFTs including displays, imagers, circuits, sensors, flexible electronics, and circuits.
Written by a team of well-reputed researchers in the field including the inventor of the IGZO TFT, Oxide Thin Film Transistors include information on: - Electronic and crystal structure of widegap oxides, covering electronic structure of n- and p-type oxide semiconductors as well as doping limit and band alignment- Device physics, covering operation principles, reliability, comparison with other TFT types, and high-frequency performance- Fabrication processes, covering deposition methods, gate insulators, and passivation layers- Applications, covering liquid crystal, light emitting diode, and electrophoretic displays, flexible electronics, imagers, and integrated circuits
Oxide Thin Film Transistors is an ideal textbook resource for students who want to learn about oxide TFTs and a useful, up-to-date reference for researchers and engineers working on oxide TFTs and in related areas.
Table of Contents
Preface ix
1 Introduction of Metal Oxide Thin Film Transistors 1
1.1 Progress of Thin Film Transistor Development 1
1.2 Progress of Metal Oxide Thin Film Transistor Development 3
1.3 Layout of Book Chapters 5
References 6
2 Semiconductor Materials in Oxide Thin Film Transistor 11
2.1 Introduction 11
2.2 Electronic and Crystal Structure of Wide-gap Oxides 11
2.2.1 Requirements for Semiconductors as Excellent TFT Channel Materials 13
2.2.2 Electronic Structure of N- and P-type Oxide Semiconductors 14
2.2.3 Doping Limit and Band Alignment 19
2.3 Amorphous Oxide Semiconductors for TFT Applications 22
2.3.1 Amorphous Semiconductors 22
2.3.2 Transparent Amorphous Oxide Semiconductors 24
2.3.2.1 Materials Design 24
2.3.2.2 Characteristic Carrier Transport Properties 29
2.3.3 Amorphous Oxide Semiconductor TFTs 31
2.3.4 Electronic States and TFT Operation 35
2.3.5 Features of Transparent Amorphous Oxide TFTs 37
2.4 Fundamental Material Issues in High-performance Oxide TFTs 39
2.4.1 CO Effect on Mobility and Stability of Oxide TFTs 39
2.4.2 Oxide Composition Effect on P-channel TFT Performance 43
2.4.3 Role of Hydrogen Impurity on Oxide TFT Characteristics 46
2.4.3.1 State and Concentration of Hydrogen 46
2.4.3.2 Carrier Generation and Hydrogen 49
2.5 Summary 53
References 54
3 Oxide Thin Film Transistor Devices 61
3.1 Introduction 61
3.2 Oxide TFT Compared to a-Si, Poly-Si, Organic, and II-VI TFTs 65
3.3 N-type, P-type, and Ambipolar Oxide TFTs 68
3.4 Oxide TFT Designs 70
3.5 Modeling of Oxide TFTs 72
3.6 Oxide TFT Reliability, Durability, and Stability Under Bias and Light Stress 88
3.7 Summary 91
References 92
4 Oxide Thin Film Transistor Fabrication Processes 101
4.1 Introduction 101
4.2 Deposition Methods for Individual Layers in Oxide TFTs 102
4.2.1 Process Influences on Individual Layer Material Properties 102
4.2.2 Gate Insulators and Passivation Layers for Oxide TFTs 105
4.3 Fabrication Processes of Oxide TFTs with Various Structures 106
4.3.1 Etch-stop Oxide TFTs 106
4.3.2 Back Channel Etch IGZO TFTs 107
4.3.3 Coplanar IGZO TFTs 109
4.3.4 Dual-gate IGZO TFTs 109
4.4 Flexible Substrate Technology for Oxide TFTs 115
4.4.1 Flexible Substrates 115
4.4.1.1 Fabrication of Polyimide Substrate 116
4.4.1.2 Laser Lift-off Detachment of Polyimide Substrate 116
4.4.1.3 Mechanical Detachment of Polyimide Substrate 117
4.4.2 Flexible IGZO TFTs on PI Substrate 119
4.4.3 Highly Flexible Oxide TFTs 123
4.5 Solution Process Prepared Oxide TFTs 126
4.5.1 Precursors for Semiconductors and Gate Insulators 126
4.5.2 Solution-Processed Oxide Semiconductors 127
4.5.3 Solution Process Prepared High-k Gate Dielectrics 130
4.5.4 Spin-coating Prepared IGZO TFTs 132
4.5.5 Spray-pyrolysis Prepared IGZO TFTs 133
4.5.6 Inkjet Printed Oxide TFTs 135
4.6 Summary 137
References 138
5 Applications of Oxide Thin Film Transistors 159
5.1 Introduction 159
5.1.1 Trend in Oxide TFT Applications 159
5.1.2 Basic TFT Functions for Applications 159
5.2 Oxide TFT Active Matrix Displays 163
5.2.1 Liquid Crystal Displays 164
5.2.2 Organic Light Emitting Device Displays 164
5.2.3 Micro-Light Emitting Device Displays 166
5.2.4 Electrophoretic Displays 167
5.2.5 Other Types of Displays 169
5.3 Oxide TFT Sensors, Sensor Arrays, and Imagers 169
5.3.1 pH Sensors 170
5.3.2 Gas Sensors 171
5.3.2.1 NO 2 Sensors 171
5.3.2.2 Humidity Sensors 173
5.3.3 Temperature Sensors 174
5.3.4 Pressure Sensors 175
5.3.5 Bio Sensors 177
5.3.6 Photo Sensors and Imagers 178
5.3.6.1 UV Sensors 178
5.3.6.2 IR and Near-IR Sensors and Imagers 180
5.3.6.3 X-ray Imagers 181
5.3.6.4 Oxide TFT-IC CMOS Imagers 183
5.3.7 Fingerprint Sensors 185
5.4 Oxide TFT-Based Circuits 188
5.4.1 Additional Oxide TFT Devices for Circuits 188
5.4.1.1 P-channel Oxide TFTs 188
5.4.1.2 Floating-gate Oxide TFT Memory Devices 189
5.4.1.3 Ferroelectric-gate Dielectric Oxide TFT Memory Devices 190
5.4.1.4 High Voltage Oxide TFTs 192
5.4.2 Inverters and Ring Oscillators 195
5.4.3 Memory Circuits 200
5.4.4 Display Drivers 201
5.4.5 Logic Circuits 202
5.4.6 Synapses 204
5.5 Oxide TFT Flexible Electronics 206
5.5.1 Bending Effect on Oxide TFT Performance 206
5.5.2 Bending Effect on Oxide TFT Memory Devices, Circuits, and Others 209
5.6 Summary 211
References 212
Index 227
