Rare-Earth Implanted MOS Devices for Silicon Photonics (eBook)

Rare-Earth Implanted MOS Devices for Silicon Photonics 3
Preface 7
Contents 11
Acronyms 15
Symbols 17
1 Silicon-Based Light Emission 19
1.1 Historical Remarks 19
1.2 Electroluminescence from Si-Based, MOS-Type Light Emitters 21
2 Microstructure 23
2.1 Device Structure and Fabrication 23
2.1.1 Layout 23
2.1.2 Rare Earth Implantation 25
2.1.3 Annealing Conditions 27
2.2 Point Defects and Diffusion 28
2.2.1 Intrinsic and Implantation Induced Defects in SiO2 28
2.2.2 Hydrogen and Other Defects in SiON 30
2.2.3 Diffusion of Rare Earth Atoms in SiO2 33
2.3 Cluster Formation and Growth 35
2.3.1 Morphology and Size Distribution 35
2.3.2 The Oxidation State of Rare Earth Clusters 39
3 Electrical Properties 40
3.1 Charge Injection and Transport in Insulators 40
3.1.1 The MOS Structure under Fowler–Nordheim Injection 40
3.1.2 Hot Electrons in SiO2 44
3.1.3 Charge Trapping and De-trapping in MNOS Systems 46
3.2 Rare Earth Implanted Unstressed Light Emitters 48
3.2.1 The Unimplanted State 48
3.2.2 Annealing Dependence 53
3.2.3 Concentration Dependence 55
3.3 Rare Earth Implanted Light Emitters Under Constant Current Injection 57
3.3.1 Low and High Injection Currents 57
3.3.2 Charge Trapping in Unimplanted and RE-Implanted Structures 58
3.3.3 Annealing Dependence 61
3.3.4 Concentration Dependence 62
3.4 The Charge Trapping and Defect Shell Model 63
3.4.1 Before Charge Injection 64
3.4.2 Physical Processes under High Electric Fields 66
3.4.3 The Different Phases of Charge Injection 67
4 Electroluminescence Spectra 70
4.1 Spectral Features 70
4.1.1 4f Intrashell Transitions in Trivalent Rare Earth Ions 70
4.1.2 Electroluminescence and Decay Time Measurement Techniques 73
4.1.3 Electroluminescence of Unimplanted MOS Structures 75
4.1.4 Electroluminescence Spectra of Rare Earth Ionsin Silicon Dioxide 76
4.1.4.1 Cerium 77
4.1.4.2 Praseodymium 77
4.1.4.3 Europium 78
4.1.4.4 Gadolinium 79
4.1.4.5 Terbium 80
4.1.4.6 Erbium 81
4.1.4.7 Thulium 82
4.1.4.8 Ytterbium 83
4.2 Injection Current Dependence 84
4.2.1 The Excitation Cross Section 84
4.2.2 Colour Shift of the Electroluminescence Spectrum 86
4.3 Concentration Quenching 89
4.3.1 The General Case 89
4.3.2 Cross Relaxation 91
4.3.3 Europium: The Interplay Between Di- and Trivalent Ions 94
4.4 Annealing Dependence 96
4.4.1 Short Time vs. Long Time Annealing 96
4.4.2 Spectral Shifts with Cluster Evolution 99
5 Electroluminescence Efficiency 101
5.1 General Considerations 101
5.1.1 Definition of Efficiency 101
5.1.2 Efficiency Measurement 103
5.1.3 Pumping of a Two-Level System 104
5.1.4 Strategies for Efficiency Tuning 106
5.2 Geometry and Material Aspects 107
5.2.1 Comparison Between Different Rare Earth Elements 107
5.2.2 The Dark Zone Model 108
5.2.3 The Influence of the Host Matrix 109
5.3 Sensitizing by Group IV Nanoclusters 112
5.3.1 Si Nanoclusters 112
5.3.1.1 The Energy Transfer Between Si Nanoclusters and Er 112
5.3.1.2 Electroluminescence 114
5.3.2 Ge Nanoclusters 117
5.3.2.1 The Inverse Energy Transfer 117
5.3.2.2 Er Concentration and Annealing Dependence 120
5.3.2.3 Microstructural Development of the Ge–Er System 124
5.3.3 Si and Ge Nanoclusters: A Short Comparison 126
5.4 Pumping by Other Rare Earth Elements 127
5.4.1 Pumping of Cerium by Gadolinium 127
5.4.2 Pumping of Erbium by Gadolinium 129
5.5 Fluorine Co-Doping 131
6 Stability and Degradation 133
6.1 Electrical Degradation 133
6.1.1 Wear-Out Mechanisms in MOS Structures 133
6.1.2 Statistical Description of the Breakdown 135
6.1.3 Charge-to-Breakdown Values Under Constant Current Injection 137
6.2 Electroluminescence Quenching 139
6.2.1 The Electroluminescence Quenching Cross-Section 139
6.2.2 The Electroluminescence Quenching Model 140
6.2.3 The Electroluminescence Reactivation Experiment 142
6.2.4 Temperature-Dependent Electroluminescence Quenching 145
6.2.5 The Anomalous Electroluminescence Quenching Behaviour of Eu 146
6.2.6 Qualitative Model of the Electroluminescence Rise Phenomenon 151
6.3 LOCOS Processing and the Use of DielectricBuffer Layers 155
6.4 Potassium Codoping 157
7 Applications 162
7.1 Requirements for Si-Based Light Emitters 162
7.2 Si-Based Optical Biosensing 164
7.2.1 Introduction 164
7.2.2 Si-Based Materials as Passive Transducers 165
7.2.3 The Concept of Direct Fluorescence Analysis 167
7.2.4 Biosensing with Si-Based, Integrated Photonic Circuits 170
References 173
Index 185