Etching of Crystals: Theory, Experiment and Application(Defects in Solids)

Defects in Solids, Volume 15: Etching of Crystals: Theory, Experiment, and Application focuses on the processes, reactions, and methodologies involved in the etching of crystals, including thermodynamics and diffusion. The publication first underscores the defects in crystals, detection of defects, and growth and dissolution of crystals. Discussions focus on thermodynamic theories, nature of pit sites, surface roughening during diffusion-controlled dissolution, growth controlled by simultaneous mass transfer and surface reactions, and chemical and thermal etching. The text then examines the theories of dissolution and etch-pit formation and the chemical aspects of the dissolution process, including catalytic reactions, dissolution of semiconductors, topochemical adsorption theories, and diffusion theories. The book tackles the solubility of crystals and complexes in solution and the kinetics and mechanism of dissolution. Topics include metallic crystals, semiconductors, stability of complexes, relationship between solubility, surface energy, and hardness of crystals, and solvents for crystals and estimation of crystal solubility in solvents other than water. The publication is a dependable source of data for readers interested in the etching of crystals.

Table of Contents:
Preface1. Defects in Crystals 1.1. Nature of Crystal Surfaces 1.2. Point Defects and Their Clusters 1.3. Dislocations 1.3.1. Edge Dislocations 1.3.2. Screw Dislocations 1.3.3. Edge Dislocations Intersecting the {111} Surface of III-V Compounds 1.3.4. Burgers Vector of a Dislocation 1.3.5. Energy Associated with Dislocations 1.3.6. Slip and Climb of Dislocations 1.4. Boundaries Between Regions of Different Orientations 1.5. p-n Homojunctions and Double Heterojunctions 1.6. Growth Striatums, Sector Boundaries and Lineages2. Detection of Defects 2.1. Growth Spirals 2.2. Chemical Etching 2.2.1. Chemical Etch Pits 2.2.2. Chemical Etch Spirals 2.2.3. Etch Hillocks 2.2.4. Electrolytic Etching 2.3. Thermal Etching 2.4. Preferential Oxidation 2.5. Preferential Dehydration and Decomposition 2.6. Ion-Bombardment Etching 2.7. Enhanced Nonradiative Recombination Techniques 2.8. Decoration Techniques 2.9. Topographic Techniques 2.10. The Photoelastic Method 2.11. Thin-Film Techniques 2.12. Advantages and Limitations of the Different Methods to Study Defects3. Growth and Dissolution of Crystals 3.1. Conditions of the Formation of Growth Nuclei 3.2. Nucleation 3.2.1. Homogeneous Nucleation 3.2.2. Heterogeneous Nucleation 3.3. Kinetics of Crystal Growth 3.3.1. Rate of Formation of Critically Sized Two-Dimensional Nuclei 3.3.2. The Normal Growth Rate According to Two-Dimensional Theories 3.3.3. The Surface Diffusion Growth Theory of Burton, Cabrera and Frank 3.3.4. Bulk Diffusion Theories 3.3.5. Equations of Steady-State Velocity of a Parallel Train of Ledges 3.4. Surface Entropy Factor 3.4.1. Surface Roughening and the a-Factor 3.4.2. Estimation of the a-Factor 3.5. The Morphology of Crystals 3.5.1. The Gibbs-Wulff Theorem for Equilibrium Forms 3.5.2. The Approach of Stranski and Kaischew 3.5.3. Periodic Bond Chains (PBCs) 3.6. Growth Forms from the Viewpoint of Growth Kinetics 3.7. Effect of Impurities on Kinetics and Growth Form 3.8. Ordered Impurity-Adsorption Layers and Growth Morphodromes 3.9. Growth Controlled by Mass and Heat Transfer 3.10. Growth Controlled by Simultaneous Mass Transfer and Surface Reactions 3.11. Reciprocity of Growth and Dissolution 3.12. Surface Roughening During Diffusion-Controlled Dissolution 3.13. Crystal-Solution Interfacial Layer 3.14. Anisotropy of the Macroscopic Dissolution Rate4. Theories of Dissolution and Etch-Pit Formation 4.1. The Nature of Pit Sites 4.2. Kinematic Theories 4.2.1. Geometric-Kinetic Theories and Stability Criteria for Hillocks and Pits 4.2.2. The Kinematic Theory of Step Motion 4.2.3. Molecular-Kinetic Theories of Dissolution 4.3. Thermodynamic Theories 4.3.1. The Nucleation Process at a Perfect Surface 4.3.2. The Formation of a Two-Dimensional Nucleus at a Dislocation Site 4.3.3. The Formation of Visible Etch Pits 4.4. Diffusion Theories 4.4.1. Vermilyea's Interfacial-Layer Theory of Macroscopic Dissolution of Ionic Crystals 4.4.2. Bohm and Kleber's Diffusion Theory of Etch-Pit Formation 4.4.3. The Mechanism of Inhibitor Diffusion for Etch-Pit Formation 4.5. Topochemical Adsorption Theories 4.5.1. Kleber's Adsorption Theory 4.5.2. Other Models 4.6. The Present-Day Situation5. Chemical Aspects of the Dissolution Process 5.1. Catalytic Reactions 5.2. Elementary Steps Involved in Dissolution 5.3. Types of Reactions During Dissolution 5.4. Formation of Oxide Layers 5.5. Dissolution of Water-Soluble Crystals 5.6. Dissolution of Water-Insoluble Ionic Crystals 5.7. Dissolution of Metals 5.8. Dissolution of Semiconductors 5.8.1. Carrier-Limited Kinetics 5.8.2. Surface-Reaction Mechanisms 5.9. Maxima in the Curves of Dissolution Rate Versus Etchant Composition 5.10. Relation Between Etch Rate and the pH of the Solution6. Solubility of Crystals and Complexes in Solution 6.1. The Structure of Solvents and Solutions 6.2. Solvation and Solubility 6.3. Solvents for Crystals and Estimation of Crystal Solubility in Solvents Other Than Water 6.4. Temperature Dependence of the Solubility 6.5. The Relationship Between Solubility, Surface Energy and Hardness of Crystals 6.6. Complexes in Solution and Their Structure 6.7. Stability of Complexes 6.8. Size and Charge of Complexes7. The Kinetics and the Mechanism of Dissolution: A Survey of Experimental Results 7.1. Alkali Halide Crystals 7.1.1. Effect of Added Salts and Their Concentration 7.1.2. Effect of Undersaturation and Addition of Water, Acids and Organic Liquids 7.1.3. Effect of Solvent and Crystallographic Orientation 7.1.4. Relation Between Concentration of Additives and Crystal Solubility 7.1.5. Effect of Etching Time 7.1.6. Influence of Stirring 7.1.7. Effect of Temperature 7.2. Other Water-Soluble Dielectrics and Insulators 7.2.1. Effect of Solvent and Crystallographic Orientation 7.2.2. Effect of Addition of Acids and Inorganic Salts 7.2.3. Effect of Temperature and Stirring 7.3. Water-Insoluble Dielectrics and Insulators 7.3.1. Etching in Aqueous Solutions of Acids, Acidic Salts and Alkalies 7.3.2. Etching in Molten Salts and Alkalies 7.3.3. Hydrothermal Etching 7.3.4. Effect of Crystallographic Orientation 7.3.5. Effect of Etching Time 7.3.6. Effect of Temperature and Addition of Viscous Liquids 7.4. Metallic Crystals 7.4.1. Etching in Acids and Acidic Salts 7.4.2. Etching in Halogens and Other Oxidizing Reagents 7.4.3. Etching in Aqueous Solutions of Alkalies 7.4.4. Etching in Solutions of Salts 7.4.5. Effect of the Etching Medium 7.4.6. Effect of Inhibitors and Etching Time 7.4.7. Effect of Crystallographic Orientation 7.5. Semiconductors 7.5.1. Etching in Aqueous Solutions of Acids, Alkalies and Salts 7.5.2. Effect of Impurities on Etch Rates and Dislocation Etch-Pit Formation 7.5.3. Etching in Molten Salts and Alkalies 7.5.4. Influence of Temperature 7.5.5. Surface Orientation Effects 7.5.6. Effect of Illumination8. Some Typical Observations on Etch Pits and the Morphology of Etched Surfaces 8.1. Etch Pits at Fresh and Aged Dislocations 8.2. Distinction Between Edge and Screw Dislocations 8.3. Positive and Negative Dislocations 8.4. Etch Pits Associated with Dislocations with Different Burgers Vector 8.5. Effect of the Inclination of Dislocations on the Morphology and Size of Etch Pits 8.6. Formation of Beaks and Etch Tunnels 8.7. Branching and Bending of Dislocations 8.8. Solution Channels, Dislocation Loops and Networks 8.9. Helical Dislocations 8.10. Star-Shaped Chemical Etch Pits 8.11. Etch Pits at Clusters of Vacancies and Impurities 8.12. Formation of Etch Hillocks by Gas Bubbles 8.13. Morphology of Etched Surfaces and Terracing of Dislocation Pits 8.13.1. Origin of Bunches 8.13.2. Observed Micromorphology of Etched Surfaces 8.13.3. Terracing of Dislocation Etch Pits 8.13.4. Formation of Block Patterns9. Morphology of Etch Pits 9.1. Factors Affecting Etch-Pit Morphology 9.2. Etch-Pit Morphology According to Ives 9.3. Analysis of the Outline of Etch Pits by Considering the Crystal Structure 9.3.1. Etch-Pit Geometry Deduced from the Atomic Arrangement 9.3.2. Etch-Pit Geometry from PBC Vectors 9.3.3. Shape of Etch Pits on Matched Cleavages 9.3.4. Simulation of Pit Morphologies 9.4. Inhibition of Dissolution Steps by Poisons and Reaction Products 9.4.1. Possible Centres for Inhibition on Cube Faces of a Halite-Type Lattice 9.4.2. Inhibiting Species and Inhibition at T-L-K Sites in Alkali Halides 9.4.3. Inhibition in Water-Insoluble Crystals 9.4.4. Formation of Circular Etch Pits 9.4.5. Relation Between J-? Curves and Etch-Pit Geometry 9.5. Effect of Optically Active Substances on Pit Morphology 9.6. Effect of Some Other Factors on Etch-Pit Morphology 9.7. Stability of Complexes and Formation of Etch Pits10. Selection of Dislocation Etchants and Polishing Solutions 10.1. Dielectrics and Insulators 10.1.1. Water-Soluble Crystals 10.1.2. Water-Insoluble Crystals 10.1.3. Guidelines for Choosing the Etchant Composition for Dielectrics and Insulators 10.2. Metallic and Semiconductor Crystals 10.2.1. Metallic Crystals 10.2.2. Semiconductors 10.2.3. Guidelines for Choosing Dislocation Etchants for Metals and Semiconductors 10.3. Surface Polishing 10.4. Reliability of Etchants 10.5. Etching and Post-Etching Procedures11. Etching Techniques in Applied Research and Development 11.1. Plastic Deformation 11.1.1. Plastic Deformation in Terms of the Dislocation Mechanism 11.1.2. Dislocation Rosettes 11.1.3. Some Other Phenomena Related to Slip and Climb of Dislocations 11.2. Fracture, Wear, Sliding and Dislocation Damping 11.3. Revelation of Defects, Impurity Distribution and Microstructures 11.3.1. Structural Characterization and Origin of Dislocations 11.3.2. Nature and Character of Dislocations 11.4. Surface Preparation 11.5. Nature and Depth of Surface Damage Caused by Mechanical Operations 11.6. Surface Orientation 11.7. Chemical Etching in Semiconductor Industry 11.7.1. Fabrication Steps in a Semiconductor Device 11.7.2. Tapering of Single and Multiple Dielectric Layers 11.7.3. Etching Profiles of Semiconductor Wafers 11.7.4. Etching Profiles of Semiconductor Multilayers 11.7.5. Etch-Stop TechniquesAppendix Table A.1. Percentage Composition of Some Liquid Reagents Frequently Used in Preparing Etching and Polishing Solutions Table A.2. Selective Etchants for Alkali Halides Table A.3. Selective Etchants for Insulators and Dielectrics Other Than Alkali Halides Table A.4. Dislocation Etchants for Metals and Metallic Alloys Table A.5. Selective Etchants for Semiconductors Table A.6. Polishing Solutions for Different Types of CrystalsReferencesList of SymbolsList of Abbreviations UsedAuthor IndexSubject Index