Carrier transport in nanoscale MOS transistors

-- Preface Ix -- Acknowledgements Xi -- 1 Emerging Technologies 1 -- 1.1 Moore's Law And The Power Crisis 1 -- 1.2 Novel Device Architectures 2 -- 1.3 High Mobility Channel Materials 5 -- 1.4 Two?-dimensional (2?-d) Materials 7 -- 1.5 Atomistic Modeling 8 -- 2 First?-principles Calculations For Si Nanostructures 12 -- 2.1 Band Structure Calculations 12 -- 2.1.1 Si Ultrathin?-body Structures 12 -- 2.1.2 Si Nanowires 17 -- 2.1.3 Strain Effects On Band Structures: From Bulk To Nanowire 20 -- 2.2 Tunneling Current Calculations Through Si/sio2/si Structures 31 -- 2.2.1 Atomic Models Of Si (001)/sio2 /si (001) Structures 32 -- 2.2.2 Current?-voltage Characteristics 33 -- 2.2.3 Sio2 Thickness Dependences 35 -- 3 Quasi?-ballistic Transport In Si Nanoscale Mosfets 41 -- 3.1 A Picture Of Quasi?-ballistic Transport Simulated Using Quantum?-corrected Monte Carlo Simulation 41 -- 3.1.1 Device Structure And Simulation Method 42 -- 3.1.2 Scattering Rates For 3?-d Electron Gas 44 -- 3.1.3 Ballistic Transport Limit 46 -- 3.1.4 Quasi?-ballistic Transport 50 -- 3.1.5 Role Of Elastic And Inelastic Phonon Scattering 51 -- 3.2 Multi?-sub?-band Monte Carlo Simulation Considering Quantum Confinement In Inversion Layers 55 -- 3.2.1 Scattering Rates For 2?-d Electron Gas 56 -- 3.2.2 Increase In Dac For Soi Mosfets 58 -- 3.2.3 Simulated Electron Mobilities In Bulk Si And Soi Mosfets 59 -- 3.2.4 Electrical Characteristics Of Si Dg?-mosfets 61 -- 3.3 Extraction Of Quasi?-ballistic Transport Parameters In Si Dg?-mosfets 64 -- 3.3.1 Backscattering Coefficient 64 -- 3.3.2 Current Drive 66 -- 3.3.3 Gate And Drain Bias Dependences 67 -- 3.4 Quasi?-ballistic Transport In Si Junctionless Transistors 69 -- 3.4.1 Device Structure And Simulation Conditions 70 -- 3.4.2 Influence Of Sr Scattering 71 -- 3.4.3 Influence Of Ii Scattering 74 -- 3.4.4 Backscattering Coefficient 75 -- 3.5 Quasi?-ballistic Transport In Gaa?-si Nanowire Mosfets 76 -- 3.5.1 Device Structure And 3dmsb?-mc Method 76 -- 3.5.2 Scattering Rates For 1?-d Electron Gas 77. 3.5.3 Id-vg Characteristics And Backscattering Coefficient 79 -- 4 Phonon Transport In Si Nanostructures 85 -- 4.1 Monte Carlo Simulation Method 87 -- 4.1.1 Phonon Dispersion Model 87 -- 4.1.2 Particle Simulation Of Phonon Transport 88 -- 4.1.3 Free Flight And Scattering 89 -- 4.2 Simulation Of Thermal Conductivity 91 -- 4.2.1 Thermal Conductivity Of Bulk Silicon 91 -- 4.2.2 Thermal Conductivity Of Silicon Thin Films 94 -- 4.2.3 Thermal Conductivity Of Silicon Nanowires 98 -- 4.2.4 Discussion On Boundary Scattering Effect 100 -- 4.3 Simulation Of Heat Conduction In Devices 102 -- 4.3.1 Simulation Method 102 -- 4.3.2 Simple 1?-d Structure 103 -- 4.3.3 Finfet Structure 106 -- 5 Carrier Transport In High?-mobility Mosfets 112 -- 5.1 Quantum?-corrected Mc Simulation Of High?-mobility Mosfets 112 -- 5.1.1 Device Structure And Band Structures Of Materials 112 -- 5.1.2 Band Parameters Of Si, Ge, And Iii?-v Semiconductors 114 -- 5.1.3 Polar?-optical Phonon (pop) Scattering In Iii?-v Semiconductors 115 -- 5.1.4 Advantage Of Utb Structure 116 -- 5.1.5 Drive Current Of Iii?-v, Ge And Si N?-mosfets 119 -- 5.2 Source?-drain Direct Tunneling In Ultrascaled Mosfets 124 -- 5.3 Wigner Monte Carlo (wmc) Method 125 -- 5.3.1 Wigner Transport Formalism 126 -- 5.3.2 Relation With Quantum?-corrected Mc Method 129 -- 5.3.3 Wmc Algorithm 131 -- 5.3.4 Description Of Higher?-order Quantized Subbands 133 -- 5.3.5 Application To Resonant?-tunneling Diode 133 -- 5.4 Quantum Transport Simulation Of Iii?-v N?-mosfets With Multi?-subband Wmc (msb?-wmc) Method 138 -- 5.4.1 Device Structure 138 -- 5.4.2 Pop Scattering Rate For 2?-d Electron Gas 139 -- 5.4.3 Id-vg Characteristics For Ingaas Dg?-mosfets 139 -- 5.4.4 Channel Length Dependence Of Sdt Leakage Current 143 -- 5.4.5 Effective Mass Dependence Of Subthreshold Current Properties 144 -- 6 Atomistic Simulations Of Si, Ge And Iii?-v Nanowire Mosfets 151 -- 6.1 Phonon?-limited Electron Mobility In Si Nanowires 151 -- 6.1.1 Band Structure Calculations 152. 6.1.2 Electron?-phonon Interaction 161 -- 6.1.3 Electron Mobility 162 -- 6.2 Comparison Of Phonon?-limited Electron Mobilities Between Si And Ge Nanowires 168 -- 6.3 Ballistic Performances Of Si And Inas Nanowire Mosfets 173 -- 6.3.1 Band Structures 174 -- 6.3.2 Top?-of?-the?-barrier Model 174 -- 6.3.3 Id-vg Characteristics 177 -- 6.3.4 Quantum Capacitances 178 -- 6.3.5 Power?-delay?-product 179 -- 6.4 Ballistic Performances Of Insb, Inas, And Gasb Nanowire Mosfets 181 -- 6.4.1 Band Structures 182 -- 6.4.2 Id-vg Characteristics 182 -- 6.4.3 Power?-delay?-product 186 -- Appendix A: Atomistic Poisson Equation 187 -- Appendix B: Analytical Expressions Of Electron?-phonon Interaction Hamiltonian Matrices 188 -- 7 2?-d Materials And Devices 191 -- 7.1 2?-d Materials 191 -- 7.1.1 Fundamental Properties Of Graphene, Silicene And Germanene 192 -- 7.1.2 Features Of 2?-d Materials As An Fet Channel 197 -- 7.2 Graphene Nanostructures With A Bandgap 198 -- 7.2.1 Armchair?-edged Graphene Nanoribbons (a?-gnrs) 199 -- 7.2.2 Relaxation Effects Of Edge Atoms 203 -- 7.2.3 Electrical Properties Of A?-gnr?-fets Under Ballistic Transport 205 -- 7.2.4 Bilayer Graphenes (blgs) 209 -- 7.2.5 Graphene Nanomeshes (gnms) 214 -- 7.3 Influence Of Bandgap Opening On Ballistic Electron Transport In Blg And A?-gnr?-mosfets 215 -- 7.3.1 Small Bandgap Regime 217 -- 7.3.2 Large Bandgap Regime 219 -- 7.4 Silicene, Germanene And Graphene Nanoribbons 221 -- 7.4.1 Bandgap Vs Ribbon Width 222 -- 7.4.2 Comparison Of Band Structures 222 -- 7.5 Ballistic Mosfets With Silicene, Germanene And Graphene Nanoribbons 223 -- 7.5.1 Id-vg Characteristics 223 -- 7.5.2 Quantum Capacitances 224 -- 7.5.3 Channel Charge Density And Average Electron Velocity 225 -- 7.5.4 Source?-drain Direct Tunneling (sdt) 226 -- 7.6 Electron Mobility Calculation For Graphene On Substrates 228 -- 7.6.1 Band Structure 229 -- 7.6.2 Scattering Mechanisms 229 -- 7.6.3 Carrier Degeneracy 231 -- 7.6.4 Electron Mobility Considering Surface Optical Phonon Scattering Of Substrates 232. 7.6.5 Electron Mobility Considering Charged Impurity Scattering 234 -- 7.7 Germanane Mosfets 236 -- 7.7.1 Atomic Model For Germanane Nanoribbon Structure 237 -- 7.7.2 Band Structure And Electron Effective Mass 238 -- 7.7.3 Electron Mobility 240 -- Appendix A: Density?-of?-states For Carriers In Graphene 242 -- References 242 -- Index 247. Hideaki Tsuchiya, Yoshinari Kamakura. Includes Bibliographical References And Index. Also Available In Print.