Metalorganic Vapor Phase Epitaxy (MOVPE)

Series Editors Arthur Willoughby University of Southampton, Southampton, UK Peter Capper Ex???Leonardo MW Ltd, Southampton, UK Safa Kasap University of Saskatchewan, Saskatoon, Canada Edited by Stuart Irvine, PhD, DSc College of Engineering, Swansea University, UK Peter Capper, PhD Ex-Leonardo MW Ltd, Southampton, UK

• List of Contributors xvForeword xviiSeries Preface xixPreface xxiSafety and Environment Disclaimer xxiii1 Introduction to Metalorganic Vapor Phase Epitaxy 1S.J.C. Irvine and P. Capper1.1 Historical Background of MOVPE 11.2 Basic Reaction Mechanisms 41.3 Precursors 81.4 Types of Reactor Cell 91.5 Introduction to Applications of MOVPE 111.5.1 AlN for UV Emitters 111.5.2 GaAs/AlGaAs VCSELS 111.5.3 Multijunction Solar Cells 121.5.4 GaAs and InP Transistors for High‐Frequency Devices 131.5.5 Infrared Detectors 141.5.6 Photovoltaic and Thermophotovoltaic Devices 141.6 Health and Safety Considerations in MOVPE 151.7 Conclusions 16References 162 Fundamental Aspects of MOVPE 19G.B. Stringfellow2.1 Introduction 192.2 Thermodynamics 202.2.1 Thermodynamics of MOVPE Growth 202.2.2 Solid Composition 242.2.3 Phase Separation 292.2.4 Ordering 312.3 Kinetics 352.3.1 Mass Transport 352.3.2 Precursor Pyrolysis 362.3.3 Control of Solid Composition 372.4 Surface Processes 402.4.1 Surface Reconstruction 412.4.2 Atomic‐Level Surface Processes 422.4.3 Effects of Surface Processes on Materials Properties 442.4.4 Surfactants 462.5 Specific Systems 522.5.1 AlGaInP 522.5.2 Group III Nitrides 532.5.3 Novel Alloys 562.6 Summary 59References 603 Column III: Phosphides, Arsenides, and Antimonides 71H. Hardtdegen and M. Mikulics3.1 Introduction 713.2 Precursors for Column III Phosphides, Arsenides, and Antimonides 733.3 GaAs‐Based Materials 743.3.1 (AlGa)As/GaAs Properties and Deposition 743.3.2 GaInP, (AlGa)InP/GaAs Properties and Deposition 793.4 InP‐Based Materials 823.4.1 InP Properties and Deposition 823.4.2 AlInAs/GaInAs/AlGaInAs Properties and Deposition 833.4.3 AlInAs/GaInAs/InP Heterostructures 843.4.4 InxGa1–xAsyP1–y Properties and Deposition 843.5 Column III Antimonides Properties and Deposition 863.5.1 Deposition of InSb, GaSb, and AlSb 873.5.2 Deposition of Ternary Column III Alloys (AlGa)Sb and (GaIn)Sb 893.5.3 Deposition of Ternary Column V Alloys In(AsSb), GaAsSb 893.5.4 Deposition of Quaternary Alloys 903.5.5 Epitaxy of Electronic Device Structures 903.5.6 Epitaxy of Optoelectronic Device Structures 953.6 In Situ Optical Characterization/Growth Control 1003.7 Conclusions 100References 1014 Nitride Semiconductors 109A. Dadgar and M. Weyers4.1 Introduction 1094.2 Properties of III‐Nitrides 1104.3 Challenges in the Growth of III‐Nitrides 1114.3.1 Lattice and Thermal Mismatch 1114.3.2 Ternary Alloys: Miscibility and Compositional Homogeneity 1134.3.3 Gas‐Phase Prereactions 1154.3.4 Doping of III‐Nitrides 1174.4 Substrates 1204.4.1 Heteroepitaxy on Foreign Substrates 1224.4.2 GaN Growth on Sapphire 1254.4.3 III‐N Growth on SiC 1264.4.4 GaN Growth on Silicon 1274.5 MOVPE Growth Technology 1304.5.1 Precursors 1304.5.2 Reactors and In Situ Monitoring 1304.6 Economic Importance 1364.6.1 Optoelectronic Devices 1374.6.2 Electronic Devices 1384.7 Conclusions 138References 1385 Metamorphic Growth and Multijunction III‐V Solar Cells 149N.H. Karam, C.M. Fetzer, X.‐Q. Liu, M.A. Steiner, and K.L. Schulte5.1 Introduction to MOVPE for Multijunction Solar Cells 1495.1.1 III‐V PV Solar Cell Opportunities and Applications 1495.1.2 Metamorphic Multijunction Solar Cells 1515.1.3 Reactor Technology for Metamorphic Epitaxy 1545.2 Upright Metamorphic Multijunction (UMM) Solar Cells 1545.2.1 Introduction and History of Upright Metamorphic Multijunctions 1545.2.2 MOVPE Growth Considerations of UMM 1565.2.3 Growth and Device Results 1585.2.4 Challenges and Future Outlook 1625.3 Inverted Metamorphic Multijunction (IMM) Solar Cells 1625.3.1 Introduction and History of Inverted Metamorphic Multijunctions 1625.3.2 MOVPE Growth Considerations of IMM 1645.3.3 Growth and Device Results 1675.3.4 Challenges and Future Outlook 1695.4 Conclusions 169References 1706 Quantum Dots 175E. Hulicius, A. Hospodková, and M. Zíková6.1 General Introduction to the Topic 1756.1.1 Definition and History 1756.1.2 Paradigm of Quantum Dots 1766.1.3 QD Types 1766.2 AIIIBV Materials and Structures 1786.2.1 QDs Embedded in the Structure 1786.2.2 Semiconductor Materials for Embedded QDs 1806.3 Growth Procedures 1816.3.1 Comparison of MBE‐ and MOVPE‐Grown QDs 1816.3.2 Growth Parameters 1826.3.3 QD Surrounding Layers 1856.4 In Situ Measurements 1936.4.1 Reflectance Anisotropy Spectroscopy of QD Growth 1936.4.2 Other Supporting In Situ Measurements 1976.5 Structure Characterization 1986.5.1 Optical: Photo‐, Magnetophoto‐, Electro‐luminescence, and Spin Detection 1986.5.2 Microscopies – AFM, TEM, XSTM, BEEM/BEES 2006.5.3 Electrical: Photocurrent, Capacitance Measurements 2026.6 Applications 2036.6.1 QD Lasers, Optical Amplifiers, and LEDs 2046.6.2 QD Detectors, FETs, Photovoltaics, and Memories 2056.7 Summary 2086.8 Future Perspectives 208Acknowledgment 209References 2097 III‐V Nanowires and Related Nanostructures: From Nitrides to Antimonides 217H.J. Joyce7.1 Introduction to Nanowires and Related Nanostructures 2177.2 Geometric and Crystallographic Properties of III‐V Nanowires 2197.2.1 Crystal Phase 2197.2.2 Growth Direction, Morphology, and Side‐Facets 2207.3 Particle‐Assisted MOVPE of Nanowires 2227.3.1 The Phase of the Particle 2227.3.2 The Role of the Particle 2247.3.3 Axial and Radial Growth Modes 2267.3.4 Self‐Assisted Growth 2287.4 Selective‐Area MOVPE of Nanowires and Nanostructures 2287.4.1 The Role of the Mask 2297.4.2 Axial and Radial Growth Modes 2307.5 Alternative Techniques for MOVPE of Nanowires 2317.6 Novel Applications of Nanowires 2317.7 Concluding Remarks 233References 2348 Monolithic III/V integration on (001) Si substrate 241B. Kunert and K. Volz8.1 Introduction 2418.2 III/V‐Si Interface 2438.2.1 Si Surfaces 2438.2.2 Interface Formation in the Presence of Impurities and MO Precursors 2478.2.3 Atomic III/V on Si Interface Structure 2498.2.4 Antiphase Domains 2518.2.5 III/V Growth on Si(001) 2528.3 Heteroepitaxy of Bulk Layers on Si 2558.3.1 Lattice‐Matched Growth on Si 2578.3.2 Metamorphic Growth on Blanket Si 2588.3.3 Selective‐Area Growth (SAG) on Si 2648.4 Conclusions 282References 2829 MOVPE Growth of Cadmium Mercury Telluride and Applications 293C.D. Maxey, P. Capper, and I.M. Baker9.1 Requirement for Epitaxy 2939.2 History 2949.3 Substrate Choices 2959.3.1 Orientation 2969.3.2 Substrate Material 2969.4 Reactor Design 2979.4.1 Process Abatement Systems 2989.5 Process Parameters 2999.6 Metalorganic Sources 2999.7 Uniformity 3009.8 Reproducibility 3029.9 Doping 3029.10 Defects 3049.11 Annealing 3079.12 In Situ Monitoring 3089.13 Background for Applications of MOVPE MCT 3089.13.1 Introduction to Infrared Imaging and Atmospheric Windows 3089.13.2 MCT Infrared Detector Market in the Modern Era 3099.14 Manufacturing Technology for MOVPE Photodiode Arrays 3119.14.1 Mesa Heterojunction Devices (MHJ) 3119.14.2 Wafer‐Scale Processing 3129.15 Advanced MCT Technologies 3129.15.1 Small‐Pixel Technology 3139.15.2 Higher Operating Temperature (HOT) Device Structures 3139.15.3 Two‐Color Array Technology 3149.15.4 Nonequilibrium Device Structures 3169.16 MOVPE MCT for Scientific Applications 3169.16.1 Linear‐Mode Avalanche Photodiode Arrays (LmAPDs) in MOVPE 3169.17 Conclusions and Future Trends for MOVPE MCT Arrays 320Definitions 321References 32210 Cadmium Telluride and Related II‐VI Materials 325G. Kartopu and S.J.C. Irvine10.1 Introduction and Historical Background 32510.2 CdTe Homoepitaxy 32710.3 CdTe Heteroepitaxy 32710.3.1 InSb 32710.3.2 Sapphire 32810.3.3 GaAs 32910.3.4 Silicon 33010.4 Low‐Temperature Growth and Alternative Precursors 33010.5 Photoassisted MOVPE 33210.6 Plasma‐Assisted MOVPE 33310.7 Polycrystalline MOCVD 33310.8 In Situ Monitoring of CdTe 33410.8.1 Mechanisms for Laser Reflectance (LR) Monitoring 33510.9 MOCVD of CdTe for Planar Solar Cells 33710.9.1 CdS and CdZnS Window Layers 33810.9.2 CdTe Absorber Layer 33810.9.3 CdCl2 Treatment Layer 34210.9.4 Photovoltaic Planar Devices 34310.10 Core‐Shell Nanowire Photovoltaic Devices 34510.11 Inline MOCVD for Scaling of CdTe 34710.12 MOCVD of CdTe for Radiation Detectors 350References 35111 ZnO and Related Materials 355V. Muñoz‐Sanjosé and S.J.C. Irvine11.1 Introduction 35511.2 Sources for the MOCVD Growth of ZnO and Related Materials 35611.2.1 Metalorganic Zinc Precursors 35611.2.2 Metalorganic Cadmium Precursors 36011.2.3 Metalorganic Magnesium Precursors 36011.2.4 Precursors for Oxygen 36111.2.5 Precursors for Doping 36311.3 Substrates for the MOCVD Growth of ZnO and Related Materials 36411.3.1 ZnO Single Crystals and ZnO Templates as Substrates 36511.3.2 Sapphire (Al2O3) 36711.3.3 Silicon 36911.3.4 Glass Substrates 37211.4 Some Techniques for the MOCVD Growth of ZnO and Related Materials 37311.4.1 Atmospheric and Low‐Pressure Conditions in Conventional MOCVD Systems 37411.4.2 MOCVD‐Assisted Processes 37611.5 Crystal Growth of ZnO and Related Materials 38011.5.1 Crystal Growth by MOCVD of ZnO Layers 38011.5.2 Crystal Growth of ZnO Nanostructures 39311.5.3 Crystal Growth of ZnO‐Related Materials 39811.5.4 Doping of ZnO and Related Materials 40011.6 Conclusions 405Acknowledgments 406References 40612 Epitaxial Systems for III‐V and III‐Nitride MOVPE 423W. Lundin and R. Talalaev12.1 Introduction 42312.2 Typical Engineering Solutions Inside MOVPE Tools 42412.2.1 Gas‐Blending System 42412.2.2 Exhaust System 43312.2.3 Reactors 43512.3 Reactors for MOVPE of III‐V Materials 43812.3.1 General Features of III‐V MOVPE 43812.3.2 From Simple Horizontal Flow to Planetary Reactors 43912.3.3 Close‐Coupled Showerhead (CCS) Reactors 44512.3.4 Rotating‐Disk Reactors 44712.4 Reactors for MOVPE of III‐N Materials 45112.4.1 Principal Differences between MOVPE of Classical III‐Vs and III‐Ns 45112.4.2 Rotating‐Disk Reactors 45412.4.3 Planetary Reactors 45512.4.4 CCS Reactors 45812.4.5 Horizontal Flow Reactors for III‐N MOVPE 45912.5 Twenty‐Five Years of Commercially Available III‐N MOVPE Reactor Evolution 462References 46413 Ultrapure Metal‐Organic Precursors for MOVPE 467D.V. Shenai‐Khatkhate13.1 Introduction 46713.1.1 MOVPE Precursor Classes and Impurities 46813.2 Stringent Requirements for Suitable MOVPE Precursors 47213.3 Synthesis and Purification Strategies for Ultrapure MOVPE Precursors 47213.3.1 Synthetic Strategies for Ultrapure MOVPE Precursors 47213.3.2 Purification Strategies for MOVPE Precursors 47613.4 MOVPE Precursors for III‐V Compound Semiconductors 48313.4.1 Group III MOVPE Precursors 48313.4.2 Group V MOVPE Precursors 48813.5 MOVPE Precursors for II‐VI Compound Semiconductors 49313.5.1 Group II MOVPE Precursors 49313.5.2 Group VI MOVPE Precursors 49613.6 MOVPE Dopants for Compound Semiconductors 49913.7 Environment, Health, and Safety (EHS) Aspects of MOVPE Precursors 50013.7.1 General Aspects and Considerations 50013.7.2 Employee and Environment Exposure Aspects 50113.7.3 Employee and Workplace Exposure Limits 50213.8 Conclusions and Future Trends 502Acknowledgments 503References 50314 Future Aspects of MOCVD Technology for Epitaxial Growth of Semiconductors 507T. Detchprohm, J.‐H. Ryou, X. Li, and R.D. Dupuis14.1 Introduction – Looking Back 50714.2 Future Equipment Development 51014.2.1 Production MOCVD 51014.2.2 R&D MOCVD 51114.2.3 MOCVD for Ultrawide‐Bandgap III‐Nitrides 51214.2.4 MOCVD for Emerging Materials 51314.2.5 Democratization of MOCVD 51414.3 Future Applications for MOCVD Research in Semiconductor Materials 51514.3.1 Heteroepitaxy 51514.3.2 Nanostructural Materials 52714.3.3 Poly, Amorphous, and Other Materials 53214.4 Past, Present, and Future Commercial Applications 53514.4.1 LEDs 53514.4.2 Lasers 53614.4.3 OEICs 53614.4.4 High‐Speed Electronics 53614.4.5 High‐Power Electronics 53714.4.6 Solar Cells 53714.4.7 Detectors 53814.5 Summary and Conclusions 538Acknowledgments 539References 539Index 549