Over the last four decades we have seen tremendous growth in semiconductor electronics. This growth has been fueled by the matured complementary metal oxide semiconductor (CMOS) technology. This comprehensive book captures the novel device options in CMOS technology that can be realized using non-silicon semiconductors. It discusses germanium, III-V materials, carbon nanotubes and graphene as semiconducting materials for three-dimensional field-effect transistors. It also covers non-conventional materials such as nanowires and nanotubes. Additionally, nanoelectromechanical switches-based mechanical relays and wide bandgap semiconductor-based terahertz electronics are reviewed as essential add-on electronics for enhanced communication and computational capabilities.
Advanced Nanoelectronics: Post-Silicon Materials and Devices begins with a discussion of the future of CMOS. It continues with comprehensive chapter coverage of: nanowire field effect transistors; two-dimensional materials for electronic applications; the challenges and breakthroughs of the integration of germanium into modern CMOS; carbon nanotube logic technology; tunnel field effect transistors; energy efficient computing with negative capacitance; spin-based devices for logic, memory and non-Boolean architectures; and terahertz properties and applications of GaN.
-Puts forward novel approaches for future, state-of-the-art, nanoelectronic devices
-Discusses emerging materials and architectures such as alternate channel material like germanium, gallium nitride, 1D nanowires/tubes, 2D graphene, and other dichalcogenide materials and ferroelectrics
-Examines new physics such as spintronics, negative capacitance, quantum computing, and 3D-IC technology
-Brings together the latest developments in the field for easy reference
-Enables academic and R&D researchers in semiconductors to "think outside the box" and explore beyond silica
An important resource for future generation CMOS electronics technology, Advanced Nanoelectronics: Post-Silicon Materials and Devices will appeal to materials scientists, semiconductor physicists, semiconductor industry, and electrical engineers.
Table of Contents
Preface xi
1 The Future of CMOS: MoreMoore or a New Disruptive Technology? 1
Nazek El-Atab and Muhammad M. Hussain
1.1 FinFET Technology 2
1.1.1 State-of-the-Art FinFETs 3
1.1.1.1 FinFET with Si Channel 3
1.1.1.2 FinFET with High-Mobility Material Channel 4
1.1.1.3 FinFET with TMD Channel 5
1.1.1.4 SOI versus Bulk FinFET 5
1.1.2 Industrial State 6
1.1.3 Challenges and Limitations 7
1.2 3D Integrated Circuit Technology 8
1.2.1 Research State 9
1.2.1.1 Thermal Management 9
1.2.1.2 Through-silicon-vias 9
1.2.1.3 Bonding in 3D IC 10
1.2.1.4 Test and Yield 12
1.2.2 Industrial State 12
1.2.3 Challenges and Limitations 13
1.3 Neuromorphic Computing Technology 13
1.3.1 State-of-the-Art NonvolatileMemory as a Synapse 14
1.3.1.1 Phase Change Memory 15
1.3.1.2 Conductive-Bridging RAM 16
1.3.1.3 Filamentary RRAM 17
1.3.2 Research Programs and Industrial State of Neuromorphic Computing 18
1.4 Quantum Computing Technology 19
1.4.1 Quantum Bit Requirement 20
1.4.2 Research State 20
1.4.2.1 Spin-Based Qubits 20
1.4.3 Superconducting Circuits for Quantum Information 21
1.4.4 Industry State 22
1.4.5 Challenges and Limitations to Quantum Computing 23
References 23
2 Nanowire Field-Effect Transistors 33
Debarghya Sarkar, Ivan S. Esqueda, and Rehan Kapadia
2.1 General Scaling Laws Leading to Nanowire Architectures 33
2.1.1 Scaling of Planar Devices and Off-state Leakage Current 33
2.1.2 FinFET and UTB Devices for Improved Electrostatics 35
2.1.3 Nanowires as the Ultimate Limit of Electrostatic Control 37
2.1.4 Quantum Effects 39
2.1.5 Drive Current 43
2.2 Nanowire Growth and Device Fabrication Approaches 43
2.2.1 Bottom-up VLS Growth 43
2.2.2 Top-down Oxidation 45
2.3 State-of-the-Art Nanowire Devices 45
2.3.1 Silicon Devices 45
2.3.2 III-V Devices 46
References 49
3 Two-dimensional Materials for Electronic Applications 55
Haimeng Zhang and HanWang
3.1 2D Materials Transistor and Device Technology 56
3.1.1 Operation and Characteristics of 2D-Materials-Based FETs 57
3.1.2 Ambipolar Property of Graphene 57
3.1.3 Important Figures of Merit 58
3.1.3.1 Ion∕Ioff Ratio 58
3.1.3.2 Subthreshold Swing 59
3.1.3.3 Cutoff Frequency and Maximum Frequency of Oscillation 59
3.1.3.4 Minimum Noise Figure 60
3.1.4 Device Optimization 61
3.1.4.1 Mobility Engineering 61
3.1.4.2 Current Saturation 62
3.1.4.3 Metal Contact 63
3.2 Graphene Electronics for Radiofrequency Applications 64
3.2.1 Experimental Graphene RF Transistors 65
3.2.2 Graphene-Based Integrated Circuits 67
3.2.2.1 Graphene Ambipolar Devices 67
3.2.2.2 Graphene Oscillators 73
3.2.2.3 Graphene RF Receivers 73
3.2.2.4 Graphene Electromechanical Devices: Resonators and RF Switches 74
3.3 MoS2 Devices for Digital Application 76
3.3.1 ExperimentalMoS2 Transistors 77
3.3.2 MoS2-Based Integrated Circuits 78
3.3.2.1 Direct-Coupled FET Logic Circuits 78
3.3.2.2 Logic Gates 79
3.3.2.3 A Static Random Access Memory Cell based on MoS2 82
3.3.2.4 Ring Oscillators based on MoS2 82
3.3.2.5 Microprocessors based on MoS2 85
References 87
4 Integration of Germanium intoModern CMOS: Challenges and Breakthroughs 91
Wonil Chung, HengWu, and Peide D. Ye
4.1 Introduction 91
4.2 Junction Formation for Germanium MOS Devices 92
4.2.1 Charge Neutrality Level and Fermi Level Pinning 92
4.2.2 Metal/Ge Contacts 93
4.2.2.1 Alleviation of FLP 93
4.2.2.2 Metal/n-Ge Contact 93
4.2.2.3 Recessed Contact Formation 94
4.3 Process Integration for Ge MOS Devices 97
4.3.1 Interface Engineering Issues 97
4.3.2 Various Gate Stack Combinations for Ge MOSFET 97
4.3.2.1 GeOx-Free Gate Stack with ALD High-κ 98
4.3.2.2 Silicon Interfacial Layer Passivation 99
4.3.2.3 Germanium (Oxy)Nitridation 99
4.3.2.4 GeO2-Based Gate Stacks 99
4.3.2.5 Rare-Earth Oxides Integrated into Germanium MOSFETs 100
4.3.3 Stress and Relaxation of Ge Layer on an Si-Based Substrate 102
4.4 State-of-the-Art Ge CMOS with Recessed Channel and S/D 102
4.4.1 Germanium CMOS Devices 102
4.4.2 Germanium CMOS Circuits 105
4.5 Steep-Slope Device: NCFET 107
4.6 Conclusion 111
References 112
5 Carbon Nanotube Logic Technology 119
Jianshi Tang and Shu-Jen Han
5.1 Introduction - Silicon CMOS Scaling and the Challenges 119
5.2 Fundamentals of Carbon Nanotube 122
5.3 Complementary Logic and Device Scalability Demonstrations 124
5.3.1 CNT NFET and Contact Engineering for CMOS Logic 124
5.3.2 Channel Length Scaling in CNTFET 127
5.3.3 Contact Length Scaling in CNTFET 132
5.4 Perspective of CNT-Based Logic Technology 138
5.4.1 CVD-Grown CNT versus Solution-Processed CNT 138
5.4.2 Purity and Placement of Solution-Processed CNTs 140
5.4.3 Variability in CNTFETs 140
5.4.4 Circuit-Level Integration 142
5.5 Summary and Outlook 142
References 143
6 Tunnel Field-Effect Transistors 151
Deblina Sarkar
6.1 Introduction 151
6.2 Tunnel Field-Effect Transistors: The Fundamentals 153
6.2.1 Working Principle 153
6.2.2 Single-Carrier Tunneling Barrier and Subthreshold Swing 154
6.3 Modeling of TFETs 156
6.4 Design and Fabrication of TFETs 161
6.4.1 Design Considerations 161
6.4.2 Current Status of Fabricated TFETs 162
6.5 Beyond Low-Power Computation 166
6.5.1 Ultrasensitive Biosensor Based on TFET 169
6.5.2 Improvement in Biosensor Response Time 173
References 175
7 Energy-Efficient Computing with Negative Capacitance 179
Asif I. Khan
7.1 Introduction 179
7.2 How a Negative Capacitance Gate Oxide Leads to Sub-60- Millivolt/Decade Switching 181
7.3 How a Ferroelectric Material Acts as a Negative Capacitor 182
7.4 Direct Measurement of Negative Capacitance in Ferroelectric 186
7.5 Properties of Negative Capacitance FETs: Modeling and Simulation 188
7.6 Experimental Demonstration of Negative Capacitance FETs 190
7.7 Speed of Negative Capacitance Transistors 195
7.8 Conclusions 195
References 196
8 Spin-Based Devices for Logic, Memory, and Non-Boolean Architectures 201
Supriyo Bandyopadhyay
8.1 Introduction 201
8.2 Spin-Based Devices 203
8.2.1 Spin Field-Effect Transistor (SPINFET) 205
8.2.2 Single Spin Logic Devices and Circuits 209
8.3 Nanomagnetic Devices: A Nanomagnet as a Giant Classical Spin 212
8.3.1 Reading Magnetization States (or Stored Bit Information) in Nanomagnets 215
8.3.2 Writing Magnetization States (or Storing Bit Information) in Nanomagnets 216
8.3.2.1 Spin-Transfer Torque 216
8.3.2.2 Spin-Transfer Torque Aided by Giant Spin Hall Effect 217
8.3.2.3 Voltage-Controlled Magnetic Anisotropy 220
8.3.2.4 Straintronics 224
8.4 Conclusion 231
Acknowledgments 232
References 232
9 Terahertz Properties and Applications of GaN 237
Berardi Sensale-Rodriguez
9.1 Introduction 237
9.1.1 Applications of Terahertz Technology 237
9.1.2 Terahertz Devices and Challenges 239
9.2 GaN: Properties and Transport Mechanisms Relevant to THz Applications 242
9.2.1 Mobility and Injection Velocity 242
9.2.2 Drift Velocity and Negative Differential Resistance 245
9.2.3 Transport due to Electron PlasmaWaves 246
9.3 GaN-based Terahertz Devices: State of the Art 249
9.3.1 High-Electron Mobility Transistors 249
9.3.2 NDR and Resonant Tunneling Devices 252
9.3.3 Quantum Cascade Lasers 254
9.3.4 Electron-Plasma-Wave-based Devices 254
References 256
Index 265
