An Essential Guide to Electronic Material Surfaces and Interfaces

Leonard Brillson is a professor of Electrical & Computer Engineering, of Physics, and a Center for Materials Research Scholar at The Ohio State University in Columbus, OH, USA. Prior to that, he directed Xerox Corporation's Materials Research Laboratory and had responsibility for Xerox's long-range physical science and technology programs at the company's research headquarters in Rochester, N.Y. He is a Fellow of IEEE, AAAS, AVS, APS, and MRS and a former Governing Board member of the American Institute of Physics. Professor Brillson has authored over 350 scientific publications in solid-state physics, microelectronics, surface science and materials science and received numerous scientific awards, including the AVS Gaede-Langmuir Award and the National Science Foundation American Competitiveness and Innovation Fellowship for leadership in the field of electrical and computer engineering.

Preface xiii

About the Companion Websites xv

1. Why Surfaces and Interfaces of Electronic Materials 1

1.1 The Impact of Electronic Materials 1

1.2 Surface and Interface Importance as Electronics Shrink 1

1.3 Historical Background 5

1.4 Next Generation Electronics 10

1.5 Problems 10

References 11

Further Reading 13

2. Semiconductor Electronic and Optical Properties 14

2.1 The Semiconductor Band Gap 14

2.2 The Fermi Level and Energy Band Parameters 15

2.3 Band Bending at Semiconductor Surfaces and Interfaces 17

2.4 Surfaces and Interfaces in Electronic Devices 17

2.5 Effects of Localized States: Traps, Dipoles, and Barriers 19

2.6 Summary 19

2.7 Problems 20

References 20

Further Reading 21

3. Electrical Measurements of Surfaces and Interfaces 22

3.1 Sheet Resistance and Contact Resistivity 22

3.2 Contact Measurements: Schottky Barrier Overview 23

3.3 Heterojunction Band Offsets: Electrical Measurements 35

3.4 Summary 38

3.5 Problems 38

References 39

Further Reading 41

4. Localized States at Surfaces and Interfaces 42

4.1 Interface State Models 42

4.2 Intrinsic Surface States 43

4.3 Extrinsic Surface States 49

4.4 The Solid State Interface: Changing Perspectives 52

4.5 Problems 52

References 53

Further Reading 54

5. Ultrahigh Vacuum Technology 55

5.1 Ultrahigh Vacuum Chambers 55

5.2 Pumps 57

5.3 Manipulators 61

5.4 Gauges 61

5.5 Residual Gas Analysis 62

5.6 Deposition Sources 62

5.7 Deposition Monitors 64

5.8 Summary 65

5.9 Problems 65

References 65

Further Reading 66

6. Surface and Interface Analysis 67

6.1 Surface and Interface Techniques 67

6.2 Excited Electron Spectroscopies 70

6.3 Principles of Surface Sensitivity 72

6.4 Multi-technique UHV Chambers 73

6.5 Summary 75

6.6 Problems 75

References 75

Further Reading 75

7. Surface and Interface Spectroscopies 76

7.1 Photoemission Spectroscopy 76

7.2 Auger Electron Spectroscopy 89

7.3 Electron Energy Loss Spectroscopy 98

7.4 Rutherford Backscattering Spectrometry 104

7.5 Surface and Interface Technique Summary 112

7.6 Problems 113

References 116

Further Reading 117

8. Dynamical Depth-Dependent Analysis and Imaging 118

8.1 Ion Beam-Induced Surface Ablation 118

8.2 Auger Electron Spectroscopy 119

8.3 X-Ray Photoemission Spectroscopy 121

8.4 Secondary Ion Mass Spectrometry 122

8.5 Spectroscopic Imaging 128

8.6 Depth-Resolved and Imaging Summary 129

8.7 Problems 129

References 130

Further Reading 130

9. Electron Beam Diffraction and Microscopy of Atomic-Scale Geometrical Structure 131

9.1 Low Energy Electron Diffraction – Principles 131

9.2 Reflection High Energy Electron Diffraction 141

9.3 Scanning Electron Microscopy 144

9.4 Transmission Electron Microscopy 145

9.5 Electron Beam Diffraction and Microscopy Summary 148

9.6 Problems 149

References 150

Further Reading 151

10. Scanning Probe Techniques 152

10.1 Atomic Force Microscopy 152

10.2 Scanning Tunneling Microscopy 155

10.3 Ballistic Electron Energy Microscopy 162

10.4 Atomic Positioning 163

10.5 Summary 164

10.6 Problems 164

References 165

Further Reading 165

11. Optical Spectroscopies 166

11.1 Overview 166

11.2 Optical Absorption 166

11.3 Modulation Techniques 168

11.4 Multiple Surface Interaction Techniques 169

11.5 Spectroscopic Ellipsometry 171

11.6 Surface Enhanced Raman Spectroscopy 171

11.7 Surface Photoconductivity 174

11.8 Surface Photovoltage Spectroscopy 175

11.9 Photoluminescence Spectroscopy 180

11.10 Cathodoluminescence Spectroscopy 181

11.11 Summary 190

11.12 Problems 191

References 192

Further Reading 192

12. Electronic Material Surfaces 193

12.1 Geometric Structure 193

12.2 Chemical Structure 196

12.3 Electronic Structure 203

12.4 Summary 209

12.5 Problems 210

References 211

Further Reading 212

13. Surface Electronic Applications 213

13.1 Charge Transfer and Band Bending 213

13.2 Oxide Gas Sensors 216

13.3 Granular Gas Sensors 217

13.4 Nanowire Sensors 217

13.5 Chemical and Biosensors 217

13.6 Surface Electronic Temperature, Pressure, and Mass Sensors 220

13.7 Summary 220

13.8 Problems 221

References 222

Further Reading 222

14. Semiconductor Heterojunctions 223

14.1 Geometrical Structure 223

14.2 Chemical Structure 230

14.3 Electronic Structure 232

14.4 Conclusions 245

14.5 Problems 246

References 247

Further Reading 248

15. Metal–Semiconductor Interfaces 249

15.1 Overview 249

15.2 Metal–Semiconductor Interface Dipoles 249

15.3 Interface States 251

15.4 Self-Consistent Electrostatic Calculations 258

15.5 Experimental Schottky Barriers 259

15.6 Interface Barrier Height Engineering 264

15.7 Atomic-Scale Control 266

15.8 Summary 272

15.9 Problems 272

References 273

Further Reading 275

16. Next Generation Surfaces and Interfaces 276

16.1 Current Status 276

16.2 Current Device Challenges 278

16.3 Emerging Directions 279

16.4 The Essential Guide Conclusions 282

Appendices

Appendix A: Glossary of Commonly Used Symbols 283

Appendix B: Table of Acronyms 286

Appendix C: Table of Physical Constants and Conversion Factors 290

Appendix D: Semiconductor Properties 291

Index 293