Mercury Cadmium Telluride: Growth, Properties and Applications(Wiley Series in Materials for Electronic & Optoelectronic Applications)

Mercury cadmium telluride (MCT) is the third most well-regarded semiconductor after silicon and gallium arsenide and is the material of choice for use in infrared sensing and imaging. The reason for this is that MCT can be ‘tuned’ to the desired IR wavelength by varying the cadmium concentration. Mercury Cadmium Telluride: Growth, Properties and Applications provides both an introduction for newcomers, and a comprehensive review of this fascinating material. Part One discusses the history and current status of both bulk and epitaxial growth techniques, Part Two is concerned with the wide range of properties of MCT, and Part Three covers the various device types that have been developed using MCT. Each chapter opens with some historical background and theory before presenting current research. Coverage includes: Bulk growth and properties of MCT and CdZnTe for MCT epitaxial growth Liquid phase epitaxy (LPE) growth Metal-organic vapour phase epitaxy (MOVPE) Molecular beam epitaxy (MBE) Alternative substrates Mechanical, thermal and optical properties of MCT Defects, diffusion, doping and annealing Dry device processing Photoconductive and photovoltaic detectors Avalanche photodiode detectors Room-temperature IR detectors

Table of Contents:
Series Preface Preface Foreword List of Contributors Part One - Growth 1 Bulk Growth of Mercury Cadmium Telluride (MCT) P. Capper 1.1 Introduction 1.2 Phase Equilibria 1.3 Crystal Growth 1.4 Conclusions References 2 Bulk growth of CdZnTe/CdTe crystals A. Noda, H. Kurita and R. Hirano 2.1 Introduction 2.2 High-purity Cd and Te 2.3 Crystal Growth 2.4 Wafer processing 2.5 Summary Acknowledgements References 3 Properties of Cd(Zn)Te (relevant to use as substrates) S. Adachi 3.1 Introduction 3.2 Structural Properties 3.3 Thermal Properties 3.4 Mechanical and Lattice Vibronic Properties 3.5 Collective Effects and Some Response Characteristics 3.6 Electronic Energy-band Structure 3.7 Optical Properties 3.8 Carrier Transport Properties References 4 Substrates for the Epitaxial growth of MCT J. Garland and R. Sporken 4.1 Introduction 4.2 Substrate Orientation 4.3 CZT Substrates 4.4 Si-based Substrates 4.5 Other Substrates 4.6 Summary and Comclusions References 5 Liquid phase epitaxy of MCT P. Capper 5.1 Introduction 5.2 Growth 5.3 Material Characteristics 5.4 Device Status 5.5 Summary and Future Developments References 6 Metal-Organic Vapor Phase Epitaxy (MOVPE) Growth C. M. Maxey 6.1 Requirement for Epitaxy 6.2 History 6.3 Substrate Choices 6.4 Reactor Design 6.5 Process Parameters 6.6 Metalorganic Sources 6.7 Uniformity 6.8 Reproducibility 6.9 Doping 6.10 Defects 6.11 Annealing 6.12 In-situ monitoring 6.13 Conclusions References 7 MBE growth of Mercury Cadmium Telluride J. Garland 7.1 Introduction 7.2 MBE Growth theory and Growth Modes 7.3 Substrate Mounting 7.4 In-situ Characterization Tools 7.5 MCT Nucleation and Growth 7.6 Dopants and Dopant Activation 7.7 Properties of MCT epilayers grown by MBE 7.8 Conclusions References Part Two - Properties 8 Mechanical and Thermal Properties M. Martyniuk, J.M. Dell and L. Faraone 8.1 Density of MCT 8.2 Lattice Parameter of MCT 8.3 Coefficient of Thermal Expansion for MCT 8.4 Elastic Parameters of MCT 8.5 Hardness and deformation characteristics of HgCdTe 8.6 Phase Diagrams of MCT 8.7 Viscosity of the MCT melt 8.8 Thermal properties of MCT References 9 Optical Properties of MCT J. Chu and Y. Chang 9.1 Introduction 9.2 Optical Constants and the Dielectric Function 9.3 Theory of Band-to-band Optical Transition 9.4 Near Band Gap Absorption 9.5 Analytic Expressions and Empirical Formulas for Intrinsic Absorption and Urbach Tail 9.6 Dispersion of the Refractive Index 9.7 Optical Constants and Related van Hover Singularities above the Energy Gap 9.8 Reflection Spectra and Dielectric Function 9.9 Multimode Model of Lattice Vibration 9.10 Phonon Absorption 9.11 Raman Scattering 9.12 Photoluminescence Spectroscopy References 10 Diffusion in MCT D. Shaw 10.1 Introduction 10.2 Self-Diffusion 10.3 Chemical Self-Diffusion 10.4 Compositional Interdiffusion 10.5 Impurity Diffusion References 11 Defects in HgCdTe – Fundamental M. A. Berding 11.1 Introduction 11.2 Ab Initio calculations 11.3 Prediction of Native Point Defect Densities in HgCdgTe 11.4 Future Challenges References 12 Band Structure and Related Properties of HgCdTe C. R. Becker and S. Krishnamurthy 12.1 Introduction 12.2 Parameters 12.3 Electronic Band Structure 12.4 Comparison with Experiment Acknowledgments References 13 Conductivity Type Conversion P. Capper and D. Shaw 13.1 Introduction 13.2 Native Defects in Undoped MCT 13.3 Native Defects in Doped MCT 13.4 Defect Concentrations During Cool Down 13.5 Change of Conductivity Type 13.6 Dry Etching by Ion Beam Milling 13.7 Plasma Etching 13.8 Summary References 14 Extrinsic Doping D. Shaw and P. Capper 14.1 Introduction 14.2 Impurity Activity 14.3 Thermal Ionization Energies of Impurities 14.4 Segregation Properties of Impurities 14.5 Traps and Recombination Centers 14.6 Donor and Acceptor Doping in LWIR and MWIR MCT 14.7 Residual Defects 14.8 Conclusions References 15 Structure and electrical characteristics of Metal/MCT interfaces R. J. Westerhout, C. A. Musca, Richard H. Sewell, John M. Dell, and L. Faraone 15.1 Introduction 15.2 Reactive/intermediately reactive/nonreactive categories 15.3 Ultrareactive/reactive categories 15.4 Conclusion 15.5 Passivation of MCT 15.6 Conclusion 15.7 Contacts to MCT 15.7 Surface Effects on MCT 15.8 Surface Structure of CdTe and MCT References 16 MCT Superlattices for VLWIR Detectors and Focal Plane Arrays James Garland 16.1 Introduction 16.2 Why HgTe-Based Superlattices 16.3 Calculated Properties 16.4 Growth 16.5 Interdiffusion 16.6 Conclusions Acknowledgements References 17 Dry Plasma Processing of Mercury Cadmium Telluride and related II- VIs Andrew Stolz 17.1 Introduction 17.2 Effects of Plasma Gases on MCT 17.3 Plasma Parameters 17.4 Characterization – Surfaces of Plasma Processed MCT 17.5 Manufacturing Issues and Solutions 17.6 Plasma Processes in Production of II-VI materials 17.7 Conclusions and Future Efforts References 18 MCT Photoconductive Infrared Detectors I. M. Baker 18.1 Introduction 18.2 Applications and Sensor Design 18.3 Photoconductive Detectors in MCT and Related Alloys 18.4 SPRITE Detectors 18.5 Conclusions on Photoconductive MCT Detectors Ackowledgements References Part Three – Applications 19 HgCdTe Photovoltaic Infrared Detectors I. M. Baker 19.1 Introduction 19.2 Advantages of the Photovoltaic Device in MCT 19.3 Applications 19.4 Fundamentals of MCT Photodiodes 19.5 Theoretical Foundations for MCT Array Technology 19.6 Manufacturing Technology for MCT Arrays 19.7 Towards “GEN III” Detectors 19.8 Conclusions and Future Trends for Photovoltaic NCT Arrays References 20 Nonequilibrium, dual-band and emission devices C. Jones and N. Gordon 20.1 Introduction 20.2 Nonequilibrium Devices 20.3 Dual-Band Devices 20.4 Emission devices 20.5 Conclusions References 21 HgCdTe Electron Avalanche Photodiodes (EAPDs) I. M. Baker and M. Kinch 21.1 Introduction and Applications 21.2 The Avalanche Multiplication Effect 21.3 Physics of MCT EAPDs 21.4 Technology of MCT EAPDs 21.5 Reported Performance of Arrays of MCT EAPDs 21.6 Laser-gated Imaging as a Practical Example of MCT EAPDs 21.7 Conclusions and Future Developments References 22 Room-temperature IR photodetectors Jozef Piotrowski and Adam Piotrowski 22.1 Introduction 22.2 Performance of Room-Temperature Infrared Photodetectors 22.3 MCT as a Material for Room-Temperature Photodetectors 22.4 Photoconductive Devices 22.5 Photoelectromagnetic, Magnetoconcentration and Dember IR Detectors 22.6 Photodiodes 22.7 Conclusions References Index

About the Author :
Dr. Peter Capper is a Materials Team Leader at BAE Systems Infrared Ltd., in Southampton, UK. James Garland is the editor of Mercury Cadmium Telluride: Growth, Properties and Applications, published by Wiley.