Imperfections and Active Centres in Semiconductors

PrefaceChapter 1 Fundamental Concepts of the Semiconductor Crystal 1.1 Introduction 1.2 Semiconduction and the Atomic Lattice of Germanium and Silicon 1.2.1 Some Elements of Crystallography 1.2.2 The Diamond Cubic Lattice and the Covalent Bond 1.2.3 Semiconduction and the Band Model 1.3 Point Defects in the Crystal 1.3.1 Vacancies and Interstitials 1.3.2 the Equilibrium Concentration of the Point DefectsChapter 2 Dislocations or Line Defects 2.1 A Survey of Dislocation Types 2.1.1 General Considerations of the Dislocation Concept 2.1.2 The Burgers Vector 2.1.3 Edge Dislocations 2.1.4 Movement of the Edge Dislocation 2.1.5 Screw Dislocations 2.1.6 Other Dislocation Types 2.2 The Motion and Generation of Dislocations 2.2.1 The Interaction of Dislocations and Jog Formation 2.2.2 The Climb of Dislocations and the Behaviour of the Jogs 2.2.3 Dislocation Sources 2.2.4 Partial Dislocations 2.2.5 Helical Dislocations and their Formation 2.3 The Geometry of the Dislocations in the Diamond Lattice 2.3.1 Structure of the Simple Dislocations 2.3.2 The Structure of Other Dislocation Types 2.3.3 the Atomic Arrangement of Partial Dislocations and Stacking FaultsChapter 3 The Detection of Dislocations by X-Ray and Other Techniques 3.1 X-Ray Diffraction and Crystal Imperfections 3.1.1 An Introduction to the Elementary Theory 3.1.2 X-Ray Line Broadening and the Crystal Quality 3.1.3 Dislocation Density from Diffraction Data 3.1.4 Crystal Assessment by the Laue and Other X-Ray Techniques 3.2 The Detection of Defects by Microscopy and Other Methods 3.2.1 X-Ray Microscopy 3.2.2 Decoration Methods and Infra-Red Microscopy 3.2.3 Electron Microscopy 3.2.4 Other Techniques for Observing the DislocationsChapter 4 Plastic Deformation and Twinning 4.1 Deformation Experiments and Behaviour of the Dislocations 4.1.1 General Observations of the Slip Mechanism 4.1.2 The Stress-Strain Relationship 4.1.3 Plastic Bending and the Distribution of the Dislocations 4.1.4 Further Deformation Experiments 4.1.5 Current Theories of the Plastic Behaviour of Semiconductor Crystals 4.1.6 Work-Hardening 4.2 Twinning in Germanium and Silicon 4.2.1 Basic Concepts and Experimental Observations 4.2.2 Deformation or Mechanical Twinning 4.2.3 Interpretation of the Twinning MechanismsChapter 5 The Growth of Single Crystal Crystals 5.1 Crystal Growing Techniques and Crystal Quality 5.1.1 The Vertical Pulling (Czochralski) Method 5.1.2 Physical Conditions and Growth Procedure 5.1.3 Horizontal Crystal Growth by Zone Melting 5.1.4 The Vertical Floating Zone Method for Silicon Crystals 5.1.5 The Stability of the Liquid Zone 5.1.6 Other Methods of Crystal Growth 5.2 The Temperature Distribution as a Crystal Growth Parameter 5.2.1 Thermal Conditions During Crystal Pulling 5.2.2 The Liquid-Solid Interface 5.2.3 External Features of the Grown Crystal 5.3 Thermal Stress in the Growth of Crystals 5.3.1 Observations of the Etch Pit Distribution 5.3.2 Thermal Stresses and the Plastic Deformation of the Crystal 5.3.3 Thermal Deformation and the Etch Pit Patterns 5.3.4 The Active Dislocations 5.3.5 Dislocation-Free Crystals 5.4 Theories of Crystal Growth Applied to Semiconductors 5.4.1 The Stepped Growth Surface 5.4.2 The Spiral Terrace 5.4.3 Crystal Growth from the Melt 5.4.4 Crystallization of the Diamond LatticeChapter 6 The Distribution and Control of Impurities 6.1 Simple Freezing and the Solute Distribution 6.1.1 Some Theoretical Considerations 6.1.2 Constitutional Supercooling in the Melt 6.1.3 The Origin of the Impurity Striations 6.2 Liquid Zone Techniques for the Distribution of Impurities 6.2.1 Zone Refining Methods 6.2.2 Solute Distribution According to Theory 6.2.3 The Ultimate Solute Distribution 6.2.4 Uniform Distribution by Zone Levelling 6.2.5 Other Methods for the Uniform Doping of CrystalsChapter 7 The Chemical and Physical Behaviour of the Impurity Elements 7.1 Methods for the Determination of Impurities in Semiconductors 7.1.1 Spectrographic Analysis 7.1.2 The Mass Spectrometer 7.1.3 Radioactivation Analysis 7.1.4 X-Ray Determination of the Lattice Parameters and Precision Density Measurements 7.1.5 Electrical Methods 7.2 The Solubility of the Active Impurities in Germanium and Silicon 7.2.1 The Nature of the Atoms 7.2.2 The Distribution Coefficient, k 7.2.3 Solid Solubility and Retrograde Solubility 7.2.4 The Determination of Solubility Data 7.2.5 Theoretical Expressions for the Distribution Coefficient 7.2.6 The Interaction of Defects and the Law of Mass Action 7.2.7 The Effect of Ion-Pairing on the Solid Solubility 7.3 Diffusion of Chemical Impurities 7.3.1 The Fundamental Laws of Diffusion 7.3.2 The Substitutional Diffusion Mechanism 7.3.3 Other Factors Affecting Diffusion 7.3.4 The Diffusion of Copper in Germanium and Silicon 7.4 The Precipitation of Impurity Elements 7.4.1 The Kinetics of Copper Precipitation in Germanium 7.4.2 Nickel Precipitation in Germanium 7.4.3 Dislocations and Other Precipitation Nuclei 7.4.4 Lithium Precipitation in Germanium and Silicon 7.5 Thermal Acceptors and the Electrical Behaviour of Semiconductors 7.5.1 Heat Treatment and the Role of Copper in Germanium 7.5.2 The Effect of Oxygen in Silicon 7.5.3 Crystal Growth Parameters and the Distribution of Oxygen in Silicon 7.5.4 Theoretical Considerations of the Thermal Behaviour 7.5.5 Oxygen in GermaniumChapter 8 Defects and the Semiconducting Properties of Germanium and Silicon 8.1 The Influence of Dislocations on the Electrical Properties 8.1.1 Changes in Resistivity Produced by Plastic Deformation 8.1.2 Scattering of the Charge Carriers by Dislocations 8.1.3 Lifetime and the Recombination of Carriers at Dislocations 8.1.4 Recombination at Low-Angle Grain Boundaries 8.2 Irradiation Damage and Semiconductor Behaviour 8.2.1 General Considerations of the Irradiation of Materials 8.2.2 Nature of the Lattice Damage 8.2.3 The Threshold Energy for Atom Displacement 8.2.4 Conductivity Variations and the Observed Energy Levels 8.2.5 Variation of the Hall Mobility 8.2.6 The Energy Level Spectra Produced by Irradiation 8.2.7 Interpretations in Terms of Theoretical Models 8.3 The Annealing Behaviour of Irradiated Germanium and Silicon 8.3.1 Observations from Thermal Annealing Experiments 8.3.2 Theoretical Explanations of the Recovery ProcessChapter 9 Etching and The Formation of Etch Pits 9.1 The Chemistry of Etching 9.1.1 Surface Preparation 9.1.2 Chemical Reactions in the Etching Process 9.1.3 Factors Controlling the Etching Rate 9.2 Physical Characteristics of the Etch Pits 9.2.1 Etch Pits on Germanium 9.2.2 Etch Pits On Silicon 9.2.3 Etch Pit Shape and Dislocation Directions 9.2.4 A Description of Spiral Etch Pits 9.3 The Correspondence Between Etch Pits and Dislocations 9.3.1 the Dislocation Boundary 9.3.2 Decoration and Other Techniques for Revealing Dislocations 9.3.3 Evidence for the Etch Pits as Real Phenomena 9.4 Theoretical Considerations of the Etching Mechanism 9.4.1 Dissolution of the Surface and Nucleation of Pits 9.4.2 Impurities in the Etchant 9.4.3 Origin of the Terraced Structure of the Etch Pits 9.4.4 The Effect On Etching of the Impurities in the Crystal 9.5 Origin of the Spiral Etch Pits 9.5.1 Helical Dislocations and the Spiral Structure 9.5.2 Other Possible Sources of the SpiralsAppendix Etchants For Ge and SiReferencesIndex