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Contents
5.1.3 Metal Gate Electrodes ......................................................... 120
5.1.4 High-k Gate Dielectrics ....................................................... 121
5.2 Multigate Transistors ........................................................................ 122
5.3 Double-Gate MOSFET ...................................................................... 123
5.4 Ω-FinFET ............................................................................................ 125
5.5 Tri-Gate FinFET ................................................................................. 127
5.6 FinFETs Using Gate-Induced Stress ............................................... 129
5.7 Stress-Engineered FinFETs .............................................................. 133
5.8 Layout Dependence .......................................................................... 138
5.9 Summary ............................................................................................ 141
Review Questions ........................................................................................ 141
References ..................................................................................................... 141
6. Noise in Strain-Engineered Devices ...................................................... 143
C. Mukherjee
6.1 Noise Mechanisms ............................................................................ 146
6.2 Fundamental Noise Sources ............................................................ 147
6.2.1 Thermal Noise ...................................................................... 147
6.2.2 Shot Noise ............................................................................. 147
6.2.3 Generation–Recombination Noise ..................................... 148
6.2.4 Random Telegraph Signal (RTS) Noise ............................. 149
6.2.5 1/f Noise ................................................................................ 151
6.3 1/f Noise in MOSFETs ...................................................................... 154
6.3.1 Number Fluctuations .......................................................... 154
6.3.2 Mobility Fluctuations .......................................................... 158
6.4 Noise Characterisation in MOSFETs .............................................. 159
6.4.1 Noise Measurements as a Diagnostic Tool....................... 159
6.5 Strain Effects on Noise in MOSFETs .............................................. 162
6.5.1 n-MOSFET under Tensile Stress ........................................ 162
6.5.2 n-MOSFET under Compressive Stress .............................. 163
6.5.3 p-MOSFET under Compressive Stress .............................. 163
6.5.4 Number Fluctuation Model under Strain ........................ 167
6.5.4.1 Mechanisms for Change in Noise PSD
under Strain .......................................................... 167
6.6 Noise in Strain-Engineered MOSFETs ........................................... 171
6.6.1 Low-Frequency Noise Measurements .............................. 172
6.6.2 Strained Si MOSFETs ........................................................... 173
6.7 Noise in Multigate FETs ................................................................... 181
6.7.1 Noise in Tri-Gate FinFET .................................................... 182
6.8 Noise in Silicon Nanowire Transistors (SNWTs) .......................... 187
6.9 Noise in Heterojunction Bipolar Transistors................................. 191
6.9.1 Low-Frequency Noise Measurement of SiGe:C HBT ..... 192
6.10 Summary ............................................................................................ 200
Review Questions ........................................................................................ 201
References ..................................................................................................... 202