Recent advances in physics, material sciences and technology have allowed the rise of new paradigms with bright prospects for digital electronics, going beyond the reach of Moore's law, which details the scaling limit of electronic devices in terms of size and power. This book presents original and innovative topics in the field of beyond CMOS electronics, ranging from steep slope devices and molecular electronics to spintronics, valleytronics, superconductivity and optical chips.
Written by globally recognized leading research experts, each chapter of this book will provide an introductory overview of their topic and illustrate the state of the art and future challenges. Aimed not only at students and those new to this field, but also at well-experienced researchers, Beyond-CMOS provides extremely clear and exciting perspectives about the technology of tomorrow, and is thus an effective tool for understanding and developing new ideas, materials and architectures.
Table of Contents
Preface xi
Alessandro CRESTI
Chapter 1 Tunnel Field-Effect Transistors Based on III-V Semiconductors 1
Marco PALA
1.1 Introduction 1
1.2 Experiments 3
1.3 Simulation of III-V-based TFETs 5
1.3.1 The k.p model in the NEGF formalism 6
1.4 SS degradation mechanisms 10
1.4.1 Electrostatic integrity 10
1.4.2 Trap-assisted tunneling 13
1.4.3 Surface roughness 16
1.5 Strategies to improve the on-state current 18
1.5.1 Strain 18
1.5.2 Broken-gap hetero-structures 22
1.5.3 Molar fraction grading of the source material 25
1.6 Conclusion 27
1.7 References 28
Chapter 2 Field-Effect Transistors Based on 2D Materials: A Modeling Perspective 33
Mathieu LUISIER, Cedric KLINKERT, Sara FIORE, Jonathan BACKMAN, Youseung LEE, Christian STIEGER and Áron SZABÓ
2.1 Introduction 33
2.1.1 Future of Moore’s law 33
2.1.2 The potential of 2D materials 38
2.2 Modeling approach 42
2.2.1 Requirements and state of the art 42
2.2.2 Maximally localized Wannier functions (MLWFs) 45
2.2.3 Towards ab initio quantum transport simulations 46
2.3 2D device performance analysis 49
2.3.1 MoS2 and other TMDs 49
2.3.2 Novel 2D materials 52
2.4 Challenges and opportunities 61
2.4.1 Electrical contacts between metals and 2D monolayers 61
2.4.2 2D mobility limiting factors 62
2.4.3 2D oxides 64
2.4.4 Advanced logic concepts 66
2.5 Conclusion and outlook 67
2.6 Acknowledgments 68
2.7 References 68
Chapter 3 Negative Capacitance Field-Effect Transistors 79
Wei CAO and Kaustav BANERJEE
3.1 Introduction 79
3.2 The rise of NC-FETs 80
3.3 Understanding NC-FETs from scratch 84
3.3.1 Electrostatics in a generic NC-FET 84
3.3.2 Formulating switching slope of a generic NC-FET 85
3.4 Fundamental challenges of NC-FET 88
3.4.1 NC does not help good FETs 88
3.4.2 Quantum capacitance may “kill” NC-FETs 91
3.5 Design and optimization of NC-FET 92
3.5.1 Designing NC-FET in the quantum capacitance limit 92
3.5.2 The role of NC nonlinearity 94
3.5.3 IMG: borrow parasitic charge for polarization in NC 96
3.5.4 A practical role of NC for FETs: voltage-loss saver 98
3.6 Appendix: A rule for polarization dynamics-based interpretation of the subthermionic SS 102
3.7 References 103
Chapter 4 Z2 Field-Effect Transistors 109
Joris LACORD
4.1 Introduction 109
4.2 Z2FET steady-state operation 112
4.2.1 Z2FET sharp switch evidence 113
4.2.2 Z2FET “S-shape” characteristic 115
4.2.3 Z2FET detailed description 116
4.3 Z2FET steady-state analytical and compact model 125
4.3.1 Z2FET steady-state analytical drain current model 125
4.3.2 Z2FET analytical evaluation of switching voltage 128
4.3.3 Z2FET compact model 131
4.4 Z2FET experimental evidence 132
4.4.1 Z2FET fabrication 132
4.4.3 Z2FET switching characteristic under gate sweep 133
4.4.4 Z2FET switching characteristic under drain sweep 134
4.5 Z2FET as 1T-DRAM 135
4.5.1 Z2FET 1T-DRAM operation description 135
4.5.2 Z2FET 1T-DRAM operation experimental evidence 136
4.6 Z2FET structure optimization 139
4.6.1 Z2fet Dgp 140
4.6.2 Z3fet 142
4.7 Z2FET advanced applications 143
4.7.1 Z2FET as ESD 143
4.7.2 Z2FET as logic switch 144
4.7.3 Z2FET as photodetector 146
4.8 Conclusion 146
4.9 References 147
Chapter 5 Two-Dimensional Spintronics 151
Matthieu JAMET, Diogo C. VAZ, Juan F. SIERRA, Josef SVĚTLÍK, Sergio O. VALENZUELA, Bruno DLUBAK, Pierre SENEOR, Frédéric BONELL and Thomas GUILLET
5.1 Introduction 151
5.2 Spintronics in 2D Rashba gases at oxide surfaces-interfaces 152
5.2.1 Emergent 2D conductivity at oxide interfaces 153
5.2.2 Rashba spin-orbit interactions 155
5.2.3 Spin-to-charge current conversion in oxide 2DEGs 156
5.2.4 Device applications and prospects 159
5.3 Spintronics in lateral spin devices in 2D materials 162
5.3.1 Introduction 162
5.3.2 Spin injection and detection 164
5.3.3 Spin precession 165
5.3.4 Mechanisms of spin relaxation 166
5.3.5 Spin transport in van der Waals heterostructures 167
5.4 2D materials in magnetic tunnel junctions 170
5.4.1 Introduction 170
5.4.2 First steps towards 2D material integration in magnetic tunnel junctions 172
5.4.3 Exfoliated and transferred devices: early results 174
5.4.4 Exfoliated and transferred devices: improvement through in situ definition 176
5.4.5 Direct CVD growth: the rise of large scale and high quality 177
5.4.6. Experimental evidences of 2D-based spin filtering in hybrid 2D-MTJs 178
5.4.7 Conclusion 181
5.5 Topological insulators in spintronics 182
5.5.1 Introduction 182
5.5.2 Spin-momentum locking and spin-charge interconversion 183
5.5.3 Materials, interfaces and fabrication methods 186
5.5.4 Spin-charge interconversion measurements 188
5.5.5 Conclusion and outlook 191
5.6 References 192
Chapter 6 Valleytronics in 2D Materials 209
Steven A. VITALE
6.1 Introduction 209
6.2 Exciton and valley physics 210
6.2.1 Introduction to valleys and excitons 211
6.2.2 Valley physics 214
6.2.3 Spin orbit coupling and exotic excitons 220
6.3 Valley lifetime, transport and operations 223
6.3.1 Valley lifetime 223
6.3.2 Valley transport 228
6.3.3 Valley operations 229
6.4 Valleytronic devices and materials 233
6.5 Valleytronic computing 238
6.5.1 Classical computing - power and performance 238
6.5.2 Classical computing - architecture 241
6.5.3 Quantum computing 242
6.5.4 Outlook 244
6.6 References 244
Chapter 7 Molecular Electronics: Electron, Spin and Thermal Transport through Molecules 251
Dominique VUILLAUME
7.1 Introduction 251
7.2 How to make a molecular junction 252
7.3 Electron transport in molecular devices: back to basics 254
7.4 Electron transport: DC and low frequency 256
7.5 Electron transport at high frequencies 263
7.6 Spin-dependent electron transport in molecular junctions 264
7.7 Molecular electronic plasmonics 268
7.8 Quantum interference and thermal transport 270
7.9 Noise in molecular junctions 275
7.10 Conclusion and further reading 279
7.11 References 280
Chapter 8 Superconducting Quantum Electronics 295
Sasan RAZMKHAH and Pascal FEBVRE
8.1 Introduction 295
8.1.1 A little bit of history 295
8.1.2 The Josephson junction 298
8.1.3 Superconducting quantum interference devices (SQUIDs) 303
8.1.4 Emergence of superconductor electronics 308
8.2 Passive superconducting electronics 309
8.2.1 Surface impedance of superconductors 309
8.2.2 Superconductor waveguides and transmission lines 311
8.2.3 Superconducting antennas 315
8.2.4 Superconducting filters 315
8.2.5 Microwave switches 316
8.3 Superconducting detectors 317
8.3.1 Transition edge sensors (TES) 318
8.3.2 Superconductor nanowire single-photon detectors (SNSPDs) 319
8.3.3 Kinetic inductance detectors (KIDs) 319
8.4 Superconducting digital electronics 321
8.4.1 Single flux quantum (SFQ) logic 322
8.4.2 Adiabatic quantum flux parametron (AQFP) logic 337
8.4.3 Towards superconducting computing 339
8.4.4 In-memory and quantum neuromorphic computing 342
8.4.5 Computer-aided design (CAD) tools 345
8.5 Superconducting quantum computing 346
8.5.1 Epistemological approach 346
8.5.2 Superconductor quantum bits (qubits) 359
8.5.3 Source of decoherence in qubits 363
8.5.4 Interface system for Josephson junction qubits 364
8.5.5 The qubit cavity 368
8.6 Cryogenic cooling 372
8.7 References 373
Chapter 9 All-Optical Chips 393
Frank BRÜCKERHOFF-PLÜCKELMANN, Johannes FELDMANN and Wolfram PERNICE
9.1 Introduction 393
9.2 Nanophotonic circuits 394
9.2.1 Dielectric waveguides 395
9.2.2 Basic photonic devices 396
9.3 Phase change photonics 398
9.3.1 Switching dynamics of phase change materials 398
9.3.2 Waveguide-coupled phase change materials 399
9.4 Photonic tensor core 401
9.4.1 Optical multiply and accumulate operations 402
9.4.2 Design of the photonic tensor core 404
9.4.3 Parallel computing by wavelength division multiplexing 405
9.4.4 Photonic tensor core prototype 407
9.5 Optical artificial neural network 409
9.5.1 Artificial neural networks 409
9.5.2 Nonlinear activation unit 411
9.5.3 Optical neuron prototype 413
9.6 Challenges and outlook 414
9.7 References 416
List of Authors 421
Index 425
