Nanoscale CMOS: Innovative Materials, Modeling and Characterization

Introduction xv
F. BALESTRA

PART 1. NOVEL MATERIALS FOR NANOSCALE CMOS 1

Chapter 1. Introduction to Part 1 3
D. LEADLEY, A. DOBBIE, V. SHAH and J. PARSONS

1.1. Nanoscale CMOS requirements 3

1.2. The gate stack – high-_ dielectrics 5

1.3. Strained channels 7

1.4. Source-drain contacts 16

1.5. Bibliography 17

Chapter 2. Gate Stacks 23
O. ENGSTRÖM, I. Z. MITROVIC, S. HALL, P. K. HURLEY, K. CHERKAOUI, S. MONAGHAN, H. D. B. GOTTLOB and M. C. LEMME

2.1. Gate-channel coupling in MOSFETs 23

2.2. Properties of dielectrics 24

2.3. Interfaces states and bulk oxide traps 29

2.4. Two ternary compounds: GdSiO and LaSiO 39

2.5. Metal gate technology 50

2.6. Future outlook 56

2.7. Bibliography 58

Chapter 3. Strained Si and Ge Channels 69
D. LEADLEY, A. DOBBIE, M. MYRONOV, V. SHAH and E. PARKER

3.1. Introduction 69

3.2. Relaxation of strained layers 74

3.3. High Ge composition Si1–xGex buffers  83

3.4. Ge channel devices 105

3.5. Acknowledgements 115

3.6. Bibliography 115

Chapter 4. From Thin Si/SiGe Buffers to SSOI 127
S. MANTL and D. BUCA

4.1. Introduction 128

4.2. Nucleation of dislocations 129

4.3. Strain relaxation and strain transfer mechanisms 131

4.4. Overgrowth of strained Si and layer optimization 134

4.5. Characterization of the elastic strain 137

4.6. SSOI wafer fabrication 141

4.7. SSOI as channel material for MOSFET devices 145

4.8. Summary 152

4.9. Bibliography 153

Chapter 5. Introduction to Schottky-Barrier MOS Architectures: Concept, Challenges, Material Engineering and Device Integration 157
E. DUBOIS, G. LARRIEU, R VALENTIN, N. BREIL and F. DANNEVILLE

5.1. Introduction 157

5.2. Challenges associated with the source/drain extrinsic contacts 158

5.3. Extraction of low Schottky barriers 166

5.4. Modulation of Schottky barrier height using low temperature dopant segregation 177

5.5. State-of-the-art device integration 191

5.6. Conclusion 195

5.7. Acknowledgements 197

5.8. Bibliography 197

PART 2. ADVANCED MODELING AND SIMULATION FOR NANO-MOSFETS AND BEYOND-CMOS DEVICES 205

Chapter 6. Introduction to Part 2 207
E. SANGIORGI

6.1. Modeling and simulation approaches for gate current computation 208

6.2. Modeling and simulation approaches for drain current computation 209

6.3. Modeling of end of the roadmap nMOSFET with alternative channel material 209

6.4. NEGF simulations of nanoscale CMOS in the effective mass approximation 210

6.5. Compact models for advanced CMOS devices 211

6.6. Beyond CMOS 211

6.7. Bibliography 212

Chapter 7. Modeling and Simulation Approaches for Gate Current Computation 213
B. MAJKUSIAK, P. PALESTRI, A. SCHENK, A. S. SPINELLI, C. M. COMPAGNONI and M. LUISIER

7.1. Introduction 213

7.2. Calculation of the tunneling probability 216

7.3. Tunneling in nonconventional devices 228

7.4. Trap-assisted tunneling 237

7.5. Models for gate current computation in commercial TCAD 243

7.6. Comparison between modeling approaches 249

7.7. Bibliography 251

Chapter 8. Modeling and Simulation Approaches for Drain Current Computation 259
M. VASICEK, D. ESSENI, C. FIEGNA and T. GRASSER

8.1. Boltzmann transport equation for MOS transistors 260

8.2. Method of moments 262

8.3. Subband macroscopic transport models 276

8.4. Comparison with device-SMC 278

8.5. Conclusions 282

8.6. Bibliography 283

Chapter 9. Modeling of End of the Roadmap nMOSFET with Alternative Channel Material 287
Q. RAFHAY, R. CLERC, G. GHIBAUDO, P. PALESTRI and L. SELMI

9.1. Introduction: replacing silicon as channel material 287

9.2. State-of-the-art in the modeling of alternative channel material devices 290

9.3. Critical analysis of the literature using analytical models 297

9.4. Conclusions 327

9.5. Bibliography 328

Chapter 10. NEGF for 3D Device Simulation of Nanometric Inhomogenities 335
A. MARTINEZ, A. ASENOV and M. PALA

10.1. Introduction 335

10.2. Variabilities for nanoscale CMOS 343

10.3. Full quantum treatment of spatial fluctuations in ultra-scaled devices 361

10.4. Bibliography 377

Chapter 11. Compact Models for Advanced CMOS Devices 381
B. IÑIGUEZ, F. LIME, A. LÁZARO and T. A. FJELDLY

11.1. Introduction 381

11.2. Electrostatics modeling issues 385

11.3. Transport modeling issues 388

11.4. 1D compact models 390

11.5. Ultimate MuGFET modeling issues: ballistic current and quantum confinement 405

11.6. Velocity saturation and channel length modulation modeling 409

11.7. Hydrodynamic transport model 411

11.8. Charge and capacitance modeling 413

11.9. Short-channel effects 420

11.10. RF and noise modeling 434

11.11. Acknowledgements 437

11.12. Bibliography 438

Chapter 12. Beyond CMOS 443
G. IANNACCONE, G. FIORI, S. REGGIANI and M. PALA

12.1. Introduction 443

12.2. Atomistic modeling of carbon-based FETs 444

12.3. Numerical simulation of CNT-FETs 447

12.4. Effective mass modeling of carbon nanotube FETs 451

12.5. CNT versus graphene nanoribbon FETs 459

12.6. Full-quantum treatment of elastic and inelastic scattering in Si and SiC GAA nanowire FETs 461

12.7. Conclusions 467

12.8. Bibliography 468

PART 3. NANOCHARACTERIZATION METHODS 471

Chapter 13. Introduction to Part 3 473
D. FLANDRE

Chapter 14. Accurate Determination of Transport Parameters in Sub-65 nm MOS Transistors 475
M. MOUIS and G. GHIBAUDO

14.1. Impact of transport on device performance in the drift-diffusion regime 476

14.2. Standard extraction techniques and their adaptation to short channel transistors 482

14.3. Alternative extraction techniques 518

14.4. Out of equilibrium transport 531

14.5. Conclusions 537

14.6. Bibliography 539

Chapter 15. Characterization of Interface Defects 545
P. HURLEY, O. ENGSTRÖM, D. BAUZA and G. GHIBAUDO

15.1. Characterization using the capacitance-voltage (C-V) response 545

15.2. Characterization using the conductance-voltage (G-V) response 550

15.3. Charge pumping 553

15.4. Low frequency noise 561

15.5. Bibliography 566

Chapter 16. Strain Determination 575
A. O’NEILL, S. OLSEN, P. DOBROSZ, R. AGAIBY and Y. TSANG

16.1. Introduction 575

16.2. Characterization requirements 575

16.3. Characterization techniques 579

16.4. Strain description 592

16.5. Bibliography 598

Chapter 17. Wide Frequency Band Characterization 603
D. FLANDRE, J.-P. RASKIN and V. KILCHYTSKA

17.1. Modified split-CV technique for reliable mobility extraction 604

17.2. Small-signal electrical characterization of FinFETs: impact of access resistances and capacitances 610

17.3. Substrate-related output conductance degradation 619

17.4. Small-signal electrical characterization of Schottky barrier MOSFETs 626

17.5. Bibliography 632

List of Authors 639

Index 649