Indium Phosphide and Related Materials: Processing,

Technology, and Devices

Avishay Katz Editor

Artech House Boston • London

Contents

Preface Chapter 1

1.1 1.2 1.3 1.4 1.5 1.6 1.7

1.8

Chapter 2 2.1 2.2

2.3

Properties of InP and Related Materials—V. Swaminathan Introduction Bonding and Crystal Structure Energy Band Structure Energy Band Structure of Alloys Heterojunctions Alloy Semiconductors Material Parameters of Alloy Semiconductors 1.7.1 Lattice Properties 1.7.2 Band Structure 1.7.3 Effective Mass 1.7.4 Elastic Properties 1.7.5 Optical Properties 1.7.6 Thermal Resistivity 1.7.7 Thermal Expansion Coefficient Summary

SIMS Analysis of InP and Related Materials—M. Geva Introduction Fundamentals of Secondary Ion Mass Spectrometry 2.2.1 Description of Technique 2.2.2 The SIMS Hardware 2.2.3 The SIMS Process 2.2.4 Static and Dynamic SIMS 2.2.5 SIMS Modes of Operation Features of SIMS Analysis 2.3.1 Sensitivity 2.3.2 Detection Limit 2.3.3 Dynamic Range 2.3.4 Depth Resolution

xiii 1 1 1 3 4 5 8

10 10 12 22 26 31 37 39 41

45 45 47 47 48 51 57 58 59 59 60 60 61

2.3.5 Spatial Resolution 62 2.3.6 Mass Resolution 62

2.4 SIMS Applications to InP and Other III-V Structures 65 2.4.1 Surface Contamination Analysis 65 2.4.2 Bulk Impurity Analysis 66 2.4.3 Layered Structures 67 2.4.4 High Depth Resolution Depth Profiling 68 2.4.5 Imaging Depth Profile 69 2.4.6 Metal-Semiconductor Interface 70

Chapter 3 Deep Levels in InP and Related Materials—W.A. Anderson and K.L. Jiao 75

3.1 Introduction 75 3.2 Theory of Deep-Level Transient Spectroscopy and Variations

of the Basic Technique 76 3.2.1 Indirect Generation-Recombination Statistics 76 3.2.2 Capacitance Transient Measurements 78 3.2.3 DLTS Theory 80 3.2.4 Variation from the Basic Technique 81

3.3 Early Work on Deep Levels in InP 82 3.4 More Recent Work on Deep Levels in InP

and Related Materials 86 3.5 Radiation Effects in InP 91 3.6 Discussion 96

Chapter 4 Low-Pressure MOVPE of InP-Based Compound Semiconductors—D. Schmitz 103

4.1 Introduction 103 4.2 The Low-Pressure MOVPE Process 105

4.2.1 Basic Considerations on the MOVPE Process 105 4.2.2 Model of Diffusion-Controlled Deposition

by MOVPE 107 4.2.3 Process Precursors 108

4.3 Equipment Design 110 4.3.1 Design of the Gas Blending System 110 4.3.2 Design of the Reaction Chamber 112 4.3.3 Substrate Rotation Technique 114 4.3.4 Electronic Safety and Control System 117 4.3.5 Exhaust Gas Treatment 117

4.4 Experimental Results and Discussion 117 4.4.1 Substrates and Preparation 118 4.4.2 Basic Process Parameters 119 4.4.3 Growth of InP-Based Materials 119

4.5 4.6

4.7

Chapter 5

5.1 5.2

5.3

5.4

5.5

5.6

Chapter 6

6.1 6.2

Doping of InP-Based Materials in Low-Pressure MOVPE Application of Low-Pressure MOVPE for Device Structures 4.6.1 Regrowth and Localized Growth of InP

and GalnAs 4.6.2 Photodiodes 4.6.3 MISFET Device Structures 4.6.4 GalnAsP Waveguides 4.6.5 Quantum Well Structures Grown

by Low-Pressure MOVPE 4.6.6 Strained Layer Device Structures 4.6.7 Visible Laser Devices Conclusion and Future Investigations

Doping of InP as Grown by Metalorganic Chemical Vapor Deposition—E.K. Byrne Introduction Shallow Donors 5.2.1 Device Applications 5.2.2 Minimizing Background Doping 5.2.3 Silicon 5.2.4 Tin 5.2.5 Sulfur 5.2.6 Selenium 5.2.7 Tellurium Shallow Acceptors 5.3.1 Device Applications 5.3.2 Zinc 5.3.3 Cadmium 5.3.4 Magnesium Deep Donors and Acceptors 5.4.1 Device Applications 5.4.2 Iron 5.4.3 Other Transition Elements Rare Earth Ions 5.5.1 Device Applications 5.5.2 Ytterbium 5.5.3 Erbium Summary

Growth of InP and Related Compounds by GSMBE and MOMBE—CR. Abernathy Introduction Equipment Design

133 139

140 141 142 142

1.44 147 149 150

155 155 156 156 156 157 159 159 160 160 161 161 162 166 168 169 169 169 171 172 172 172 173 174

177 177 178

6.3

6.4

6.5

6.6

Chapter 7

7.1 7.2

7.3

7.4 7.5

Chapter 8 8.1 8.2

6.2.1 GSMBE 6.2.2 MOMBE Growth Kinetics 6.3.1 GSMBE 6.3.2 MOMBE Material Quality 6.4.1 GSMBE 6.4.2 MOMBE Doping 6.5.1 Elemental Sources: GSMBE 6.5.2 Elemental Sources: MOMBE 6.5.3 Gaseous Sources: MOMBE Devices 6.6.1 GSMBE 6.6.2 MOMBE

Ion Beam Processing of InP and Related Materials —S.J. Pearton and U.K. Chakrabarti Introduction Ion Implantation for Doping 7.2.1 InP 7.2.2 InGaAs 7.2.3 AlInAs 7.2.4 InGaAsP 7.2.5 InSb 7.2.6 InAs Ion Implantation for Isolation 7.3.1 InP 7.3.2 InGaAs 7.3.3 AlInAs 7.3.4 InGaAsP 7.3.5 InSb 7.3.6 InAs 7.3.7 Thermally Stable Isolation Schemes Rapid Thermal Annealing Dry Etching 7.5.1 Ion Milling 7.5.2 Plasma Etching Techniques and Chemistries 7.5.3 Electron Cyclotron Resonance Plasma Etching

Dry Etching of In-Based Semiconductors—T.R. Hayes Introduction Overview of Etch Techniques

178 182 187 187 188 194 194 194 199 199 202 203 206 206 206

211 211 212 212 216 218 218 218 220 222 223 227 231 234 235 235 235 239 243 243 250 261

277 277 279

8.3 Etch Chemistries and Mechanisms 281 8.3.1 Halogen-B ased Chemistries 281 8.3.2 Hydrocarbon-Based Chemistries 285 8.3.3 Halogen and Hydrocarbon Mixtures 288

8.4 Etch-Induced Damage 289 8.5 Etch Diagnostics 293 8.6 Epitaxial Growth on Dry-Etched Surfaces 295 8.7 Applications 296

8.7.1 Gratings for Distributed Feedback Lasers 296 8.7.2 Active Channels and Mesas 297 8.7.3 Mirrors and Facets 299

8.8 Summary 301

Chapter 9 Ohmic Contacts to InP and Related Materials—A. Katz 307 9.1 Introduction 307 9.2 Fundamentals of Metal/InP Ohmic Contacts 310

9.2.1 Interfacial Reactions 310 9.2.2 Electrical Properties 313 9.2.3 Correlation Between Ohmic Contact Microstructure

and Electrical Properties 315 9.2.4 Intrinsic Thermal and Mechanical Stresses 319

9.3 Elemental Metal-InP Contacts 321 9.3.1 Au-Based Contacts 321 9.3.2 Near-Noble Transition Metal-Based Contacts 324 9.3.3 Refractory Metal-Based (W, W-Alloys) Contacts 327

9.4 Conclusions, Summary, and Future Directions 328

Chapter 10 Issues for Dielectric Technology for InP MISFETs —U.K. Chakrabarti 337

10.1 Introduction 337 10.2 InP MISFET 338 10.3 Dielectric Technology for InP MISFET 339

10.3.1 Requirements of the Dielectric 339 10.3.2 Requirements of Dielectric Deposition

Technology 340

Chapter 11 InGaAsP Quantum Well Lasers—N.K. Dutta 351 11.1 Introduction 351 11.2 Energy Levels 352 11.3 Gain and Recombination 355

11.3.1 Density of States 356 11.3.2 Gain and Radiative Recombination 357 11.3.3 Nonradiative Recombination 358

11.4 Single QW and MQW Lasers 359

11.5 Laser Structures 361 11.5.1 Broad-Area Lasers 362 11.5.2 Index-Guided Lasers 363 11.5.3 Low-Threshold Lasers 366

11.6 Single-Frequency Lasers 367 11.6.1 DFB Lasers 367 11.6.2 DBR Lasers 371

11.7 Strained QW Lasers 373 11.7.1 InGaAs Strained QW Lasers 373 11.7.2 Dynamic Characteristics 375

Chapter 12 Heterostructure Bipolar Transistors—B. Jalali and R.N. Nottenburg 379

12.1 Introduction 379 12.2 Basic Device Concepts 379 12.3 Available Heterostructure Systems 381 12.4 Current Voltage Characteristics 383 12.5 Base Transport 386 12.6 Collector Transport and High-Frequency Characteristics 388 12.7 High Doping Limit in the Base 395 12.8 Integrated Circuits 396 12.9 Summary 403

Chapter 13 Optimization and Fabrication of Metal Contacts for Photovoltaic Solar Cells—T.A. Gessert and T.J. Courts 407

13.1 Introduction 407 13.2 The Physics of Solar Cell Grid Modeling 410

13.2.1 Photovoltaic Solar Cell Equations 410 13.2.2 Top Contact Grid Modeling Equations 411 13.2.3 Concentrator Solar Cells ' 414

13.3 Solar Cell Metallization and Modeling Studies 415 13.3.1 Contact Resistance of the Back and Front Contact 416 13.3.2 Grid Metal Resistivity 420 13.3.3 Grid Metal Linewidfh Considerations 426 13.3.4 Adhesion, Intermetallic Stress, and Diffusion

of the Grid Line 431 13.3.5 Photolithographic Considerations 432

13.4 Future Trends and Conclusions 435 13.4.1 Mechanically Stacked, Four-Terminal,

Two-Junction Solar Cell Metallization 436 13.4.2 Monolithic, Three-Terminal, Two-Junction

Solar Cell Metallization 436 13.4.3 Conclusions 437

Index 443