Growth of High Permittivity Dielectrics by High Pressure Sputtering from Metallic Targets (eBook)

Supervisor’s Foreword 7
Abstract 10
Acknowledgements 12
Contents 14
Abbreviations 17
Symbols 19
1 Introduction 22
1.1 Historical Evolution 22
1.2 CMOS Devices Scaling 24
1.3 High ? Dielectrics 26
1.3.1 Gadolinium Oxide 29
1.3.2 Scandium Oxide 29
1.3.3 Gadolinium Scandate 29
1.4 Metal Gate Electrodes 30
1.4.1 Scavenging Effect 30
1.5 Alternative Substrates 31
1.6 High Pressure Sputtering (HPS) 32
1.7 Alternatives Structures 33
1.8 Outline of the Thesis 34
References 35
2 Fabrication Techniques 42
2.1 High Pressure Sputtering (HPS) 42
2.2 Glow Discharge Optical Spectroscopy (GDOS) 45
2.2.1 System I (Monocromator) 46
2.2.2 System II (Spectrometer) 47
2.3 Electron Beam (e-beam) Evaporation 48
2.3.1 SiOx Acting as Field Oxide 50
2.3.2 Metallic Electrodes 50
2.4 Lithography Process 50
2.4.1 Positive Photoresist 51
2.4.2 Negative Photoresist 52
2.5 Rapid Thermal Annealing (RTA) 52
2.6 MIS Fabrication 53
2.6.1 Process Without Field Oxide (FOX) 53
2.6.2 Process with FOX 55
2.7 Substrates 57
2.7.1 Semiconductor Materials 57
2.7.1.1 Si Wafers 57
2.7.1.2 InP Substrates 57
2.7.2 Substrate Surface Cleaning 58
2.7.2.1 Si Wafers 58
2.7.2.2 InP Wafers 59
References 59
3 Characterization Techniques 61
3.1 Structural Characterization Techniques 62
3.1.1 Fourier Transform Infrared Spectroscopy (FTIR) 62
3.1.2 Grazing Incidence X Ray Diffraction (GIXRD) 65
3.1.3 X Ray Reflectometry (XRR) 66
3.1.4 X Ray Photoelectron Spectroscopy (XPS) 67
3.1.5 Transmission Electron Microscopy (TEM) 68
3.2 Electrical Characterization Techniques 69
3.2.1 MIS Capacitors 69
3.2.1.1 Ideal MIS Capacitor in Equilibrium 70
3.2.1.2 Ideal MIS Capacitor Under Bias 70
3.2.1.3 Real MIS Structure 71
3.2.2 Capacitive Behavior of MIS Devices: C–Vgate Characterization 72
3.2.2.1 Effects of QINS in the C–Vgate Characteristics 73
3.2.2.2 Effects of Dit in the C–Vgate Characteristics 74
3.2.2.3 Effects of the Oxide Trapped Charge in the C–Vgate Characteristics 76
3.2.3 Interfacial State Density (Dit) Determination 76
3.2.3.1 Conductance Method 76
3.2.3.2 Deep Level Transient Spectroscopy (DLTS) 78
3.2.4 Leakage Current Density Measurements 79
References 80
4 Thermal Oxidation of Gd2O3 83
4.1 Experimental Method 83
4.2 Results and Discussion 84
4.2.1 Plasma Characterization of Metallic Gd Sputtered in Ar 84
4.2.2 Physical Characterization of the Thermally Oxidized GdOx Films 86
4.2.3 Electrical Characterization of MIS Devices with Thermally Oxidized Gd2O3 90
4.2.4 TEM Analysis of MIS Devices 92
4.3 Summary and Conclusions 94
References 94
5 Plasma Oxidation of Gd2O3 and Sc2O3 96
5.1 Experimental Method 96
5.2 Results and Discussion 97
5.2.1 Feasibility of the Two-Step Deposition Process for Gd2O3 and Sc2O3 97
5.2.1.1 Plasma Characterization of Metallic Gd Sputtered in Ar/O2 Atmosphere 97
5.2.1.2 Plasma Characterization of Metallic Sc Sputtered in Pure Ar and Mixed Ar/O2 Atmospheres 99
5.2.1.3 Structural Characterization of the Plasma Oxidized Gd2O3 Films 101
5.2.1.4 Structural Characterization of the Plasma Oxidized Sc2O3 Films 103
5.2.1.5 Electrical Characterization of MIS Devices with Plasma Oxidized Gd2O3 and Sc2O3 103
5.2.2 Optimization of the Two-Step Deposition Process for Gd2O3 106
5.2.2.1 Oxidation Power Effect 106
5.2.2.2 Initial Metal Deposition Time Influence 109
5.2.2.3 Oxidation Time 111
5.2.3 Effect of FGA Temperature on Optimized MIS Devices with Plasma Oxidized Gd2O3 116
5.2.4 Electrical Characterization of Optimized MIS Devices with Plasma Oxidized Sc2O3 121
5.3 Summary and Conclusions 124
References 125
6 Gadolinium Scandate 128
6.1 Experimental Method 129
6.2 Results and Discussion 129
6.2.1 Plasma Characterization 129
6.2.2 Physical Characterization 130
6.2.3 Electrical Characterization 134
6.3 Summary and Conclusions 141
References 141
7 Interface Scavenging 144
7.1 Experimental Method 144
7.2 Results and Discussion 145
7.2.1 Thick Ti Layers as Top Electrode with Gd2O3 145
7.2.2 Optimization of the Scavenging Effect for Plasma Oxidized Gd2O3 147
7.2.3 Scavenging Effect for Plasma Oxidized Sc2O3 153
7.2.4 Scavenging Effect for Plasma Oxidized Gd0.9Sc1.1O3 155
7.3 Summary and Conclusions 157
References 158
8 Gd2O3 on InP Substrates 160
8.1 Experimental Method 160
8.2 Results and Discussion 161
8.2.1 Feasibility of Plasma Oxidized Gd2O3 Deposited on InP Substrates 161
8.2.2 Optimized Devices with Gd2O3 on InP 164
8.2.3 Interface Scavenging with InP 167
8.3 Summary and Conclusions 170
References 170
9 Conclusions and Future Work 173
9.1 Conclusions 173
9.2 Future Work 175
Curriculum Vitae 176
Education 176
Publication List 177
Conference Contributions 178
Patent 180
Research Experience 180
Teaching Experience 181