Table of contents 4.6.2 Silicon crystal fabrication 4.6.3 Rapid thermal processing 4.7 Summary points 4.8 Homework 4.9 Suggested Readings and Reference 5. ENGINEERING ELECTRONIC STRUCTURE 195 5.1 Linking atomic orbitals to bands 5. 1. 1 Homopolar semiconductors 5.1.2 Heteropolar compounds 5.2 LCAO: from atomic orbitals to bands 5.3 Common semiconductor energy band 5.4 Pressure and temperature dependence 5.5 Applications 226 5.5. 1 Experimental band structures 5.5.2 Gunn diodes 5.6 Summary points 5.7 Homework 233 5.8 Suggested readings references 235 6 SEMICONDUCTOR ALLOYS 237 6. 1 Alloy selection 6.1.1 Overview 6. 1.2 Choosing alloy constituents 241 6.2 Semiconductor alloy thermodynamics 245 6.2. 1 Regular solution theory revisited 6.2.2 Ternary and quaternary solutions 249 6.2.3 More mechanisms for alloy orde 6.3 Band gap bowing 255 6.3. 1 Binary and pseudobinary alloys 6.3.2 Bowing in quaternary alloys 260 6.4 Silicon-germanium alloys 6.4.1 Structure and solubility 262 6.4.2 Band gap engineering 6.4.3 Alloying and carrier mobility 6.5 Metastable semiconductor alloys 6.6 Applications 6.6.1 Heterojunction bipolar transistors 72 6. 7 Summary points 6.8 Homework 6.9 Suggested rea references 285195 5.1 Linking atomic orbitals to bands ...................................................................196 5.1.1 Homopolar semiconductors ................................................................197 5.1.2 Heteropolar compounds ......................................................................201 5.2 LCAO: from atomic orbitals to bands...........................................................206 5.3 Common semiconductor energy bands .........................................................215 5.4 Pressure and temperature dependence...........................................................223 5.5 Applications...................................................................................................226 5.5.1 Experimental band structures..............................................................226 5.5.2 Gunn diodes ........................................................................................228 5.6 Summary points.............................................................................................232 5.7 Homework .....................................................................................................233 5.8 Suggested readings & references...................................................................235 237 6.1 Alloy selection...............................................................................................238 6.1.1 Overview .............................................................................................238 6.1.2 Choosing alloy constituents ................................................................241 6.2 Semiconductor alloy thermodynamics..........................................................245 6.2.1 Regular solution theory revisited ........................................................245 6.2.2 Ternary and quaternary solutions........................................................249 6.2.3 More mechanisms for alloy ordering ..................................................252 6.3 Band gap bowing...........................................................................................255 6.3.1 Binary and pseudobinary alloys..........................................................255 6.3.2 Bowing in quaternary alloys ...............................................................260 6.4 Silicon-germanium alloys..............................................................................261 6.4.1 Structure and solubility .......................................................................262 6.4.2 Band gap engineering..........................................................................264 6.4.3 Alloying and carrier mobility..............................................................267 6.5 Metastable semiconductor alloys ..................................................................268 6.6 Applications...................................................................................................272 6.6.1 Heterojunction bipolar transistors.......................................................272 6.6.2 Solar cells ............................................................................................276 6.7 Summary points.............................................................................................280 6.8 Homework .....................................................................................................282 6.9 Suggested readings & references...................................................................285 Table of Contents xiii 4.7 Summary points.............................................................................................189 4.8 Homework .....................................................................................................191 4.9 Suggested Readings and References.............................................................194 4.6.2 Silicon crystal fabrication ...................................................................180 4.6.3 Rapid thermal processing....................................................................187 5. ENGINEERING ELECTRONIC STRUCTURE 6. SEMICONDUCTOR ALLOYS