VLSI Fabrication Principles: Silicon and Gallium Arsenide, 2nd Edition

1 Material Properties 1

1.1 Physical Properties 3

1.2 Crystal Structure 13

1.3 Crystal Axes and Planes 16

1.4 Orientation Effects 19

1.5 Point Defects 23

1.6 Dislocations 45

1.7 Electronic Properties of Defects 53

Tables 58

References 64

Problems 67

2 Phase Diagrams and Solid Solubility 69

2.1 Unitary Diagrams 70

2.2 Binary Diagrams 70

2.3 Solid Solubility 88

2.4 Ternary Diagram 91

References 99

Problem 100

3 Crystal Growth and Doping 102

3.1 Starting Growth and Doping 102

3.2 Growth from the Melt 106

3.3 Considerations for Proper Crystal Growth 113

3.4 Doping in the Melt 120

3.5 Semi-Insulating Gallium Arsenide 129

3.6 Properties of Melt-Grown Crystals 132

3.7 Solution Growth 134

3.8 Zone Processes 135

3.9 Properties of Zone-Processed Crystals 141

Tables 142

References 145

Problems 149

4 Diffusion 150

4.1 The Nature of Diffusion 151

4.2 Diffusion in a Concentration Gradient 154

4.3 The Diffusion Equation 171

4.4 Impurity Behavior: Silicon 183

4.5 Impurity Behavior: Gallium Arsenide 197

4.6 Diffusion Systems 202

4.7 Diffusion Systems for Silicon 209

4.8 Special Problems in Silicon Diffusion 217

4.9 Diffusion Systems for Gallium Arsenide 224

4.10 Evaluation Techniques for Diffused Layers 235

Tables 246

References 251

Problems 256

5 Epitaxy 258

5.1 General Considerations 261

5.2 Molecular Beam Epitaxy 273

5.3 Vapor-Phase Epitaxy 283

5.4 VPE Processes for Silicon 296

5.5 VPE Processes for Gallium Arsenide 313

5.6 Liquid-Phase Epitaxy 330

5.7 LPE Systems 340

5.8 Heteroepitaxy 345

5.9 Evaluation of Epitaxial Layers 348

Tables 356

References 358

Problems 366

6 Ion Implantation 368

6.1 Penetration Range 370

6.2 Implantation Damage 389

6.3 Annealing 393

6.4 Ion Implantation Systems 407

6.5 Process Considerations 416

6.6 High-Energy Implants 430

6.7 High-Current Implants 431

6.8 Application to Silicon 432

6.9 Application to Gallium Arsenide 437

Tables 442

References 443

Problems 449

7 Native Films 451

7.1 Thermal Oxidation of Silicon 452

7.2 Thermal Nitridation of Silicon 483

7.3 Thermal Oxidation of Gallium Arsenide 485

7.4 Anodic Oxidation 487

7.5 Plasma Processes 495

7.6 Evaluation of Native Films 498

Tables 500

References 503

Problems 508

8 Deposited Films 510

8.1 Film Deposition Methods 511

8.2 Film Characteristics 522

8.3 Films for Protection and Masking 527

8.4 Films for Doping 546

8.5 Films for Interconnections 548

8.6 Films for Ohmic Contacts 556

8.7 Films for Schottky Diodes 570

Tables 576

References 578

9 Etching and Cleaning 587

9.1 Wet Chemical Etching 589

9.2 Dry Physical Etching 613

9.3 Dry Chemical Etching 620

9.4 Reactive Ion Etching 625

9.5 Chemically Assisted Ion Beam Techniques 636

9.6 Etching-Induced Damage 638

9.7 Cleaning 639

Tables 646

References 654

Problems 661

10 Lithographic Processes 662

10.1 Photoreactive Materials 664

10.2 Pattern Generation and Mask-Making 669

10.3 Pattern Transfer 674

10.4 Advanced Techniques 685

10.5 Problem Areas 696

11 Device and Circuit Fabrication 704

11.1 Isolation 705

11.2 Self-Alignment 712

11.3 Local Oxidation 714

11.4 Planarization 721

11.5 Metallization 726

11.6 Gettering 728

11.7 Mos-Based Silicon Microcircuits 730

11.8 BJT-Based Silicon Microcircuits 749

11.9 Gallium Arsenide Microcircuits 778

Tables 790

References 790

Appendix The Mathematics of Diffusion 801

A.1 Solutions for a Constant Diffusion Coefficient 802

A.2 Solution for a Time-Dependent Diffusion Coefficient 811

A.3 Solution for Concentration-Dependent Diffusion Coefficients 813

A.4 Determination of the Diffusion Constant 815

References 817

Index 819