Part Ⅰ Semiconductor Fundamentals 1
Chapter 1 Semiconductors: A General Introduction 3
1.1 General Material Properties 3
1.1.1 Composition 3
1.1.2 Purity 5
1.1.3 Structure 6
1.2 Crystal Structure 6
1.2.1 The Unit Cell Concept 7
1.2.2 Simple 3-D Unit Cells 8
1.2.3 Semiconductor Lattices 9
1.2.4 Miller Indices 12
1.3 Crystal Growth 16
1.3.1 Obtaining Ultrapure Si 16
1.3.2 Single-Crystal Formation 17
1.4 Summary 19
Problems 19
Chapter 2 Carrier Modeling 23
2.1 The Quantization Concept 23
2.2 Semiconductor Models 25
2.2.1 Bonding Model 26
2.2.2 Energy Band Model 26
2.2.3 Carriers 29
2.2.4 Band Gap and Material Classification 31
2.3 Carrier Properties 32
2.3.1 Charge 32
2.3.2 Effective Mass 32
2.3.3 Carrier Numbers in Intrinsic Material 34
2.3.4 Manipulation of Carrier Numbers—Doping 35
2.3.5 Carrier-Related Terminology 40
2.4 State and Carrier Distributions 40
2.4.1 Density of States 41
2.4.2 The Fermi Function 42
2.4.3 Equilibrium Distribution of Carriers 46
2.5 Equilibrium Carrier Concentrations 49
2.5.1 Formulas for n and p 49
2.5.2 Alternative Expressions for n and p 52
2.5.3 ni and the np Product 53
2.5.4 Charge Neutrality Relationship 57
2.5.5 Carrier Concentration Calculations 59
2.5.6 Determination of EF 61
2.5.7 Carrier Concentration Temperature Dependence 65
2.6 Summary and Concluding Comments 67
Problems 69
Chapter 3 Carrier Action 75
3.1 Drift 75
3.1.1 Definition-Visualization 75
3.1.2 Drift Current 76
3.1.3 Mobility 79
3.1.4 Resistivity 85
3.1.5 Band Bending 89
3.2 Diffusion 94
3.2.1 Definition-Visualization 94
3.2.2 Hot-Point Probe Measurement 97
3.2.3 Diffusion and Total Currents 98
Diffusion Currents 98
Total Currents 99
3.2.4 Relating Diffusion Coeffcients/Mobilities 99
Constancy of the Fermi Level 99
Current Flow Under Equilibrium Conditions 101
Einstein Relationship 101
3.3 Recombination-Generation 105
3.3.1 Definition-Visualization 105
Band-to-Band Recombination 105
R-G Center Recombination 105
Auger Recombination 107
Generation Processes 107
3.3.2 Momentum Considerations 107
3.3.3 R-G Statistics 110
Photogeneration 110
Indirect Thermal Recombination-Generation 112
3.3.4 Minority Carrier Lifetimes 116
General Information 116
A Lifetime Measurement 116
3.4 Equations of State 120
3.4.1 Continuity Equations 121
3.4.2 Minority Carrier Diffusion Equations 122
3.4.3 Simplifications and Solutions 124
3.4.4 Problem Solving 124
Sample Problem No.1 124
Sample Problem No.2 128
3.5 Supplemental Concepts 131
3.5.1 Diffusion Lengths 131
3.5.2 Quasi-Fermi Levels 132
3.6 Summary and Concluding Comments 136
Problems 138
Chapter 4 Basics of Device Fabrication 149
4.1 Fabrication Processes 149
4.1.1 Oxidation 149
4.1.2 Diffusion 152
4.1.3 Ion Implantation 155
4.1.4 Lithography 159
4.1.5 Thin-Film Deposition 162
Evaporation 162
Sputtering 162
Chemical Vapor Deposition （CVD） 164
4.1.6 Epitaxy 164
4.2 Device Fabrication Examples 165
4.2.1 pn Junction Diode Fabrication 166
4.2.2 Computer CPU Process Flow 166
4.3 Summary 174
R1 Part Ⅰ Supplement and Review 175
Alternative/Supplemental Reading List 175
Figure Sources/Cited References 177
Review List of Terms 178
Part Ⅰ—Review Problem Sets and Answers 179
Part ⅡA pn Junction Diodes 193
Chapter 5 pn Junction Electrostatics 195
5.1 Preliminaries 195
5.1.1 Junction Terminology/Idealized Profiles 195
5.1.2 Poisson's Equation 197
5.1.3 Qualitative Solution 198
5.1.4 The Built-in Potential （Vbi） 203
5.1.5 The Depletion Approximation 206
5.2 Quantitative Electrostatic Relationships 209
5.2.1 Assumptions/Definitions 209
5.2.2 Step Junction with VA = 0 210
Solution for p 210
Solution for ? 210
Solution for V 212
Solution for xn and xp 213
5.2.3 Step Junction with VA ≠ 0 215
5.2.4 Examination/Extrapolation of Results 219
5.2.5 Linearly Graded Junctions 223
5.3 Summary 226
Problems 227
Chapter 6 pn Junction Diode: Ⅰ-V Characteristics 235
6.1 The Ideal Diode Equation 235
6.1.1 Qualitative Derivation 235
6.1.2 Quantitative Solution Strategy 241
General Considerations 241
Quasineutral Region Considerations 242
Depletion Region Considerations 243
Boundary Conditions 244
“Game Plan” Summary 246
6.1.3 Derivation Proper 247
6.1.4 Examination of Results 249
Ideal Ⅰ-V 249
The Saturation Current 250
Carrier Currents 254
Carrier Concentrations 255
6.2 Deviations from the Ideal 260
6.2.1 Ideal Theory Versus Experiment 260
6.2.2 Reverse-Bias Breakdown 263
Avalanching 264
Zener Process 268
6.2.3 The R-G Current 270
6.2.4 VA --→ Vbi High-Current Phenomena 277
Series Resistance 278
High-Level Injection 279
6.3 Special Considerations 281
6.3.1 Charge Control Approach 282
6.3.2 Narrow-Base Diode 284
Current Derivation 284
Limiting Cases/Punch-Through 286
6.4 Summary and Concluding Comments 288
Problems 289
Chapter 7 pn Junction Diode: Small-Signal Admittance 301
7.1 Introduction 301
7.2 Reverse-Bias Junction Capacitance 301
7.2.1 General Information 301
7.2.2 C-V Relationships 305
7.2.3 Parameter Extraction/Profiling 309
7.2.4 Reverse-Bias Conductance 313
7.3 Forward-Bias Diffusion Admittance 315
7.3.1 General Information 315
7.3.2 Admittance Relationships 318
7.4 Summary 323
Problems 324
Chapter 8 pn Junction Diode: Transient Response 327
8.1 Turn-Off Transient 327
8.1.1 Introduction 327
8.1.2 Qualitative Analysis 329
8.1.3 The Storage Delay Time 333
Quantitative Analysis 333
Measurement 334
8.1.4 General Information 338
8.2 Turn-On Transient 338
8.3 Summary 343
Problems 344
Chapter 9 Optoelectronic Diodes 347
9.1 Introduction 347
9.2 Photodiodes 349
9.2.1 pn Junction Photodiodes 349
9.2.2 p-i-n and Avalanche Photodiodes 352
p-i-n Photodiodes 352
Avalanche Photodiodes 355
9.3 Solar Cells 356
9.3.1 Solar Cell Basics 356
9.3.2 Efficiency Considerations 357
9.3.3 Solar Cell Technology 360
9.4 LEDs 361
9.4.1 General Overview 361
9.4.2 Commercial LEDs 362
9.4.3 LED Packaging and Photon Extraction 366
Part ⅡB BJTs and Other Junction Devices 369
Chapter 10 BJT Fundamentals 371
10.1 Terminology 371
10.2 Fabrication 374
10.3 Electrostatics 378
10.4 Introductory Operational Considerations 380
10.5 Performance Parameters 382
Emitter Ef 382
ciency 382
Base Transport Factor 383
Common Base d.c.Current Gain 383
Common Emitter d.c.Current Gain 384
10.6 Summary 385
Problems 385
Chapter 11 BJT Static Characteristics 389
11.1 Ideal Transistor Analysis 389
11.1.1 Solution Strategy 389
Basic Assumptions 389
Notation 390
Diffusion Equations/Boundary Conditions 390
Computational Relationships 392
11.1.2 General Solution （W Arbitrary） 393
Emitter/Collector Region Solutions 393
Base Region Solution 394
Performance Parameters/Terminal Currents 395
11.1.3 Simplified Relationships （W 《 LB） 397
△PB （x） in the Base 398
Performance Parameters 398
11.1.4 Ebers-Moll Equations and Model 403
11.2 Deviations from the Ideal 407
11.2.1 Ideal Theory/Experiment Comparison 407
11.2.2 Base Width Modulation 410
11.2.3 Punch-Through 412
11.2.4 Avalanche Multiplication and Breakdown 414
Common Base 414
Common Emitter 414
11.2.5 Geometrical Effects 420
Emitter Area ≠ Collector Area 420
Series Resistances 421
Current Crowding 421
11.2.6 Recombination-Generation Current 422
11.2.7 Graded Base 423
11.2.8 Figures of Merit 424
11.3 Modern BJT Structures 426
11.3.1 Polysilicon Emitter BJT 426
11.3.2 Heterojunction Bipolar Transistor （HBT） 429
11.4 Summary 432
Problems 433
Chapter 12 BJT Dynamic Response Modeling 443
12.1 Small-Signal Equivalent Circuits 443
12.1.1 Generalized Two-Port Model 443
12.1.2 Hybrid-Pi Models 446
12.2 Transient （Switching） Response 449
12.2.1 Qualitative Observations 449
12.2.2 Charge Control Relationships 452
12.2.3 Quantitative Analysis 454
Turn-on Transient 454
Turn-off Transient 456
12.2.4 Practical Considerations 457
12.3 Summary 458
Problems 459
Chapter 13 PNPN Devices 463
13.1 Silicon Controlled Rectifier （SCR） 463
13.2 SCR Operational Theory 465
13.3 Practical Turn-on/Turn-off Considerations 470
13.3.1 Circuit Operation 470
13.3.2 Additional Triggering Mechanisms 471
13.3.3 Shorted-Cathode Configuration 471
13.3.4 di/dt and dv/dt Effects 472
13.3.5 Triggering Time 473
13.3.6 Switching Advantages/Disadvantages 473
13.4 Other PNPN Devices 474
Chapter 14 MS Contacts and Schottky Diodes 477
14.1 Ideal MS Contacts 477
14.2 Schottky Diode 483
14.2.1 Electrostatics 483
Built-in Voltage 483
p,?, V 485
Depletion Width 486
14.2.2 Ⅰ-V Characteristics 487
14.2.3 a.c.Response 493
14.2.4 Transient Response 496
14.3 Practical Contact Considerations 497
14.3.1 Rectifying Contacts 497
14.3.2 Ohmic Contacts 498
14.4 Summary 500
Problems 501
R2 Part Ⅱ Supplement and Review 505
Alternative/Supplemental Reading List 505
Figure Sources/Cited References 506
Review List of Terms 507
Part Ⅱ—Review Problem Sets and Answers 508
Part Ⅲ Field Effect Devices 523
Chapter 15 Field Effect Introduction—The J-FET and MESFET 525
15.1 General Introduction 525
15.2 J-FET 530
15.2.1 Introduction 530
15.2.2 Qualitative Theory of Operation 531
15.2.3 Quantitative ID-VD Relationships 536
15.2.4 a.c.Response 547
15.3 MESFET 550
15.3.1 General Information 550
15.3.2 Short-Channel Considerations 552
Variable Mobility Model 553
Saturated Velocity Model 554
Two-Region Model 555
15.4 Summary 557
Problems 557
Chapter 16 MOS Fundamentals 563
16.1 Ideal Structure Definition 563
16.2 Electrostatics—Mostly Qualitative 565
16.2.1 Visualization Aids 565
Energy Band Diagram 565
Block Charge Diagrams 566
16.2.2 Effect of an Applied Bias 567
General Observations 567
Specific Biasing Regions 568
16.3 Electrostatics—Quantitative Formulation 571
16.3.1 Semiconductor Electrostatics 571
Preparatory Considerations 571
Delta-Depletion Solution 576
16.3.2 Gate Voltage Relationship 580
16.4 Capacitance-Voltage Characteristics 584
16.4.1 Theory and Analysis 584
Qualitative Theory 584
Delta-Depletion Analysis 590
16.4.2 Computations and Observations 591
Exact Computations 591
Practical Observations 595
16.5 Summary and Concluding Comments 599
Problems 600
Chapter 17 MOSFETs—The Essentials 611
17.1 Qualitative Theory of Operation 611
17.2 Quantitative ID -VD Relationships 617
17.2.1 Preliminary Considerations 617
Threshold Voltage 617
Effective Mobility 618
17.2.2 Square-Law Theory 620
17.2.3 Bulk-Charge Theory 625
17.2.4 Charge-Sheet and Exact-Charge Theories 628
17.3 a.c.Response 630
17.3.1 Small-Signal Equivalent Circuits 630
17.3.2 Cutoff Frequency 633
17.3.3 Small-Signal Characteristics 634
17.4 Summary 637
Problems 638
Chapter 18 Nonideal MOS 645
18.1 Metal-Semiconductor Workfunction Difference 645
18.2 Oxide Charges 650
18.2.1 General Information 650
18.2.2 Mobile Ions 653
18.2.3 The Fixed Charge 658
18.2.4 Interfacial Traps 662
18.2.5 Induced Charges 668
Radiation Effects 668
Negative-Bias Instability 669
18.2.6 △VGSummary 670
18.3 MOSFET Threshold Considerations 674
18.3.1 VT Relationships 675
18.3.2 Threshold, Terminology, and Technology 676
18.3.3 Threshold Adjustment 678
18.3.4 Back Biasing 680
18.3.5 Threshold Summary 681
Problems 684
Chapter 19 Modern FET Structures 691
19.1 Small Dimension Effects 691
19.1.1 Introduction 691
19.1.2 Threshold Voltage Modification 694
Short Channel 694
Narrow Width 697
19.1.3 Parasitic BJT Action 698
19.1.4 Hot-Carrier Effects 700
Oxide Charging 700
Velocity Saturation 700
Velocity Overshoot/Ballistic Transport 701
19.2 Select Structure Survey 702
19.2.1 MOSFET Structures 702
LDD Transistors 702
DMOS 703
Buried-Channel MOSFET 704
SiGe Devices 704
SOI Structures 705
19.2.2 MODFET （HEMT） 707
Problems 710
R3 Part Ⅲ Supplement and Review 713
Alternative/Supplemental Reading List 713
Figure Sources/Cited References 714
Review List of Terms 717
Part Ⅲ—Review Problem Sets and Answers 718
Appendices 733
Appendix A Elements of Quantum Mechanics 733
A.1 The Quantization Concept 733
A.1.1 Blackbody Radiation 733
A.1.2 The Bohr Atom 735
A.1.3 Wave-Particle Duality 737
A.2 Basic Formalism 739
A.3 Electronic States in Atoms 741
A.3.1 The Hydrogen Atom 741
A.3.2 Multi-Electron Atoms 744
Appendix B MOS Semiconductor Electrostatics—Exact Solution 749
Definition of Parameters 749
Exact Solution 750
Appendix C MOS C-V Supplement 753
Appendix D MOS I-V Supplement 755
Appendix E List of Symbols 757
Appendix M MATLAB Program Script 771
Exercise 10.2 （BJT_Eband） 771
Exercise 11.7 （BJT） and Exercise 11.10 （BJTplus） 774
Exercise 16.5 （MOS_CV） 778
Index 781