Thermophysical Properties and Measuring Technique of Ge-Sb-Te Alloys for Phase Change Memory (eBook)

Preface 5
Contents 7
About the Author 10
1 Introduction 11
1.1 Background 11
1.2 Thermal Conductivity Theory 16
1.2.1 Electronic Thermal Conductivity (?e) 16
1.2.2 Phonon Thermal Conductivity 19
1.2.3 Other Mechanisms 20
1.3 Previous Studies on Ge–Sb–Te Alloy System 21
1.3.1 Phase Diagram 21
1.3.2 Crystallographic Structure 24
1.3.3 Electrical Resistivity 26
1.3.4 Thermal Conductivity 28
1.3.5 Optical Properties 28
References 29
2 Establishment of the Hot-Strip Method for Thermal Conductivity Measurements of Ge–Sb–Te Alloys 32
2.1 Introduction 32
2.2 Establishment of Hot-Strip Method 34
2.2.1 Principle 34
2.2.2 Measurement Setup Modifications 35
2.2.3 Parameters ? and R0 Optimization 38
2.3 Sample and Experiment Procedure 41
2.4 Reliability Verification of the Hot-Strip Method 42
2.5 Application of the Hot-Strip Method to Ge–Sb–Te Alloys 44
2.5.1 Characterization of Sb2Te3 Alloys Before and After Measurements 44
2.5.2 Thermal Conductivity Results of Sb2Te3 Alloy 45
2.6 Uncertainty in Thermal Conductivity Measurement of Sb2Te3 Alloy 49
2.6.1 Uncertainty in Current (I) 49
2.6.2 Uncertainty in  ?R?? , XT and  d?Vdlnt 49
2.6.3 Uncertainty in Distance Between Potential Terminals (l) 51
2.6.4 Sensitivity Coefficients 51
2.6.5 Combined Standard Uncertainty 51
2.7 Conclusions 52
References 52
3 Thermal Conductivities of Ge–Sb–Te Alloys 54
3.1 Introduction 54
3.2 Sample and Experimental Procedure 56
3.3 Characterization of Sb–Te and GeTe–Sb2Te3 Alloys 58
3.3.1 Characterization of Sb–Te Alloys 58
3.3.2 Characterization of GeTe–Sb2Te3 Alloys 62
3.4 Thermal Conductivities of Sb–Te and GeTe–Sb2Te3 Alloys 64
3.4.1 Thermal Conductivities of Sb–Te Alloys 64
3.4.2 Thermal Conductivities of GeTe–Sb2Te3 Pseudobinary Alloys 68
3.5 Uncertainty in Thermal Conductivity Measurements of Ge–Sb–Te Alloys 72
3.5.1 Uncertainty in Current (I) 72
3.5.2 Uncertainty in  ?R?? , XT and  d?Vdlnt 74
3.5.3 Uncertainty in Distance Between Potential Terminals (l) 74
3.5.4 Sensitivity Coefficients 74
3.5.5 Combined Standard Uncertainty 75
3.6 Comparison with Reported Data 75
3.7 Conclusions 76
References 77
4 Electrical Resistivities of Ge–Sb–Te Alloys 79
4.1 Introduction 79
4.2 Experimental 81
4.2.1 Sample 81
4.2.2 Four-Terminal Method 83
4.2.3 Measurement Setup and Procedure 83
4.3 Characterization of GeTe–Sb2Te3 Alloys 86
4.4 Electrical Resistivities of GeTe–Sb2Te3 Alloys 88
4.5 Uncertainty in Electrical Resistivity Measurements of GeTe–Sb2Te3 Pseudobinary Alloys 92
4.5.1 Uncertainty in Resistance (R) 92
4.5.2 Uncertainty in Diameter of Sample (d) 92
4.5.3 Uncertainty in Distance Between Inner Electrodes (l) 94
4.5.4 Sensitivity Coefficients 94
4.5.5 Combined Standard Uncertainty 95
4.6 Comparison with Reported Data 95
4.7 Conclusions 96
References 97
5 Thermal Conduction Mechanisms and Prediction Equations of Thermal Conductivity for Ge–Sb–Te Alloys 99
5.1 Introduction 99
5.2 Thermal Conduction Mechanisms 100
5.2.1 Structural Similarity 100
5.2.2 Sb–Te Binary Alloys 102
5.2.3 Ternary GeTe–Sb2Te3 Pseudobinary Alloys 109
5.2.4 GeTe Alloy 115
5.3 Prediction Equations of Thermal Conductivity 116
5.3.1 Sb–Te Binary Alloys 117
5.3.2 Sb2Te3–GeTe Pseudobinary Alloys 121
5.4 Conclusions 124
References 124
6 Densities of Ge–Sb–Te Alloys 126
6.1 Introduction 126
6.2 Sessile Drop Method 127
6.2.1 Sample 127
6.2.2 Sessile Drop Method 128
6.2.3 Substrate Selection 130
6.2.4 Parameter Calibration 130
6.2.5 Archimedean Method 131
6.3 Density Results 132
6.3.1 Substrate Selection 132
6.3.2 Parameter Calibration 134
6.3.3 Density Results 134
6.4 Discussion 137
6.4.1 Comparison with Reported Data 137
6.4.2 Application Discussion 140
6.5 Conclusions 141
References 141
7 Summary and Conclusions 143