Transport in Metal-Oxide-Semiconductor Structures (eBook)

Transport in Metal-Oxide-Semiconductor Structures 2
Preface 4
Contents 6
List of Symbols, Abbreviations and Physical Constants 9
1 Introduction 12
References 15
2 The MOS Structure 16
2.1…Introduction 16
2.2…A Simple Physical Approach Applied to MOS Structure 16
2.2.1 Basic Concepts and Quantities 17
2.2.2 Definition of Potentials 18
2.3…Ideal MOS Capacitor 18
2.3.1 Accumulation 19
2.3.2 Depletion 20
2.3.3 Inversion 22
Low frequency Capacitance 22
High Frequency capacitance 23
2.4…The Actual (Non-ideal) MOS Structure 24
2.4.1 The Metal-Silicon Work Function Difference 24
2.4.2 Effect of the Charge Distributed in the Oxide 25
References 26
3 The MOS Oxide and Its Defects 28
3.1…Introduction 28
3.2…Oxide Growth Techniques 28
3.3…Thermal Oxidation 29
3.3.1 Dry Oxidation 30
3.3.2 Wet Oxidation 31
Bubblers 31
Flash System 31
Dryox System 32
3.4…Anodic Oxidation 32
3.5…Rapid Thermal Oxidation 32
3.6…MOS Oxide Defects 32
3.6.1 The Interface Trapped Charge 33
3.6.2 The Fixed Oxide Charge 35
3.6.3 The Oxide Trapped Charge 36
3.6.4 The Mobile Ionic Charge 37
References 38
4 Review of Transport Mechanism in Thin Oxides of MOS Devices 40
4.1…Introduction 40
4.2…Electronic Conduction 40
4.2.1 The Schottky (or Thermionic) Conduction 41
4.2.2 The Tunneling Conduction 41
4.2.3 The Fowler--Nordheim Conduction 43
4.2.4 The Frenkel-Poole Conduction 43
4.2.5 The Hopping Conduction 43
4.2.6 The Space Charge-Limited Current 44
Weak Injection 44
Strong Injection 44
Very Strong Injection 44
4.3…Ionic Conduction 45
4.3.1 Ionic Current Transport Equation 46
Drift Current 46
Diffusion Current 46
4.4…Summary 46
References 47
5 Experimental Techniques 49
5.1…Introduction 49
5.2…High Frequency MOS C--V Measurement under BTS 51
5.2.1 Determination of the Flat-Band Voltage 51
5.2.2 How the Mobile Charges Effect can be Separated 52
5.2.3 Theory 53
5.2.4 Experimental Results and Discussion 54
5.3…TVS Technique 55
5.3.1 Theory 58
5.3.2 Earlier Investigation 59
5.4…TSIC Technique 61
5.4.1 Theory 62
5.5…Charge-pumping Associated with BTS Technique 63
5.5.1 Theory 63
5.5.2 Separation of the Mobile Charge Effect 64
5.5.3 Experimental Results and Discussion 65
References 67
6 Theoretical Approaches of Mobile Ions Density Distribution Determination 69
6.1…Introduction 69
6.2…Problem Formulation 70
6.3…Earlier Analytical Approaches 71
6.3.1 Analytical Approach of Chou 71
6.3.2 Analytical Approach of Tangena et al. 73
6.3.3 Analytical Approach of Romanov et al. 75
6.4…Empirical Model 77
6.4.1 General Formulation 78
6.4.2 First Empirical Model 79
6.4.3 Results and Discussions 80
6.4.4 Second Empirical Model 81
Uniform Rectangular Distribution 81
The Exponential Distribution 83
The Gaussian Distribution 84
6.4.5 Results and Discussion 84
6.5…Numerical Approach 85
6.5.1 Numerical Solution 86
6.5.2 Simulation Results and Discussion 88
6.5.3 Experimental and Simulation Results 89
6.6…Conclusion 90
References 91
7 Theoretical Model of Mobile Ions Distribution and Ionic Current in the MOS Oxide 93
7.1…Introduction 93
7.2…Theoretical Model of Mobile Ions Density Distribution 94
7.2.1 Preliminary Considerations 94
7.2.2 One-Dimensional Distribution Model of Mobile Ions 96
7.3…I--V Characteristic Determination 102
7.4…Experimental Results and Discussion 103
7.5…Conclusion 110
References 111
Index 113