Page 8 - Electrical Properties of Materials

Contents vii

7.5 The effective mass 112
7.6 The effective number of free electrons 114
7.7 The number of possible states per band 115
7.8 Metals and insulators 117
7.9 Holes 117
7.10 Divalent metals 119
7.11 Finite temperatures 120
7.12 Concluding remarks 121
Exercises 122

8 Semiconductors

8.1 Introduction 123
8.2 Intrinsic semiconductors 123
8.3 Extrinsic semiconductors 128
8.4 Scattering 132
8.5 A relationship between electron and hole densities 134
8.6 III–V and II–VI compounds 136
8.7 Non-equilibrium processes 140
8.8 Real semiconductors 141
8.9 Amorphous semiconductors 143
8.10 Measurement of semiconductor properties 143
8.10.1 Mobility 143
8.10.2 Hall coefficient 146
8.10.3 Effective mass 146
8.10.4 Energy gap 147
8.10.5 Carrier lifetime 151
8.11 Preparation of pure and controlled-impurity single-crystal semiconductors 151
8.11.1 Crystal growth from the melt 151
8.11.2 Zone refining 152
8.11.3 Modern methods of silicon purification 154
8.11.4 Epitaxial growth 154
8.11.5 Molecular beam epitaxy 156
8.11.6 Metal–organic chemical vapour deposition 156
8.11.7 Hydride vapour phase epitaxy (HVPE) for nitride devices 157
Exercises 158

9 Principles of semiconductor devices

9.1 Introduction 161
9.2 The p–n junction in equilibrium 161
9.3 Rectification 166
9.4 Injection 168
9.5 Junction capacity 170
9.6 The transistor 171
9.7 Metal–semiconductor junctions 176
9.8 The role of surface states; real metal–semiconductor junctions 178
9.9 Metal–insulator–semiconductor junctions 180
9.10 The tunnel diode 183
9.11 The backward diode 186