Charge-Trapping Non-Volatile Memories (eBook)

Panagiotis Dimitrakis is at the Institute of Advanced Materials Physicochemical Processes Nanotechnology & Microsystems at the National Centre for Scientific Research, Greece.

Contents 5
1 Materials and Device Reliability in SONOS Memories 6
1.1 Introduction 6
1.2 History of SONOS Memory Devices 6
1.3 Floating Gate and SONOS Memories 8
1.4 SONOS Memory Devices 9
1.4.1 Traps in the SONOS Stack 11
1.4.2 Program and Erase of SONOS FET 12
1.5 SONOS Memory Cells 15
1.5.1 1T Cell 15
1.5.2 Split Gate Cell 16
1.5.3 2T SONOS Cell 16
1.5.4 MirrorBit® Cell 17
1.6 SONOS Memory Cell Architectures 17
1.6.1 1T-Cell 17
1.6.2 2T Cell 18
1.6.3 MirrorBit Cell 19
1.7 Leakage Currents in SONOS Cells 22
1.8 SONOS Memory Cell Processing 23
1.9 SONOS Memory Cell Reliability 24
1.9.1 Memory Cell Disturbs 25
1.9.2 SONOS Endurance 32
1.9.3 Data Retention 35
1.9.4 Temperature Acceleration—Activation Energy (Ea) 36
1.10 SONOS Memory Stack Enhancements—Impact on Reliability 37
1.10.1 BE-SONOS 38
1.10.2 TANOS Device 39
1.10.3 Other Improvements to Charge Trap Memory Stack 41
1.10.4 Novel Materials for Charge Trap Layer 45
1.11 Embedded Charge Trap Memories 50
1.12 Challenges of Integration of SONOS Memory Module 52
1.13 Charge Trap Memory—Present and Future 54
1.14 NVM Roadmap 56
References 56
2 Charge-Trap-Non-volatile Memory and Focus on Flexible Flash Memory Devices 60
2.1 Nanotechnology and Nanomaterials 60
2.2 Properties of Nanomaterials 62
2.3 Coulomb Blockade and Single-Electron Tunnelling 65
2.4 Current Status of Nanomaterials Used for Memory Storage—The Charge Can Trapped in Their Available Energy States 66
2.5 Synthesis of Silicon Nanowires 67
2.5.1 Vapour–Liquid–Solid Growth Mechanism 68
2.5.2 Choice of Catalyst Material for Silicon Nanowires Growth 69
2.5.3 In and Sn Catalyst Materials for Silicon Nanowires Growth 71
2.6 Flexible Electronic Flash Memory Devices 74
2.6.1 Introduction to Flash Memory Technology 74
2.7 Flash Memory Structure 78
2.8 Working Mechanisms of the Flash Memory Cell 79
2.8.1 Fowler–Nordheim Tunnelling 80
2.8.2 Channel-Hot-Electron Injection Process 81
2.8.3 Reading Operation 82
2.9 Choice of the Dielectric Material: Silicon Nitride 83
2.10 A Brief History of Flexible Flash Memory Devices 84
2.11 Review of the Current Status of Flexible Flash Memories 86
2.12 Summary 87
References 88
3 Hybrid Memories Based on Redox Molecules 95
3.1 Introduction 95
3.2 Molecular Electronics Overview 96
3.3 Memory Cells Based on Redox Molecules 99
3.3.1 Molecules in Hybrid Devices 99
3.3.2 Ferrocene 100
3.3.3 Porphyrins 107
3.3.4 Polyoxomatalates 109
3.4 Conclusions and Outlook 121
References 122
4 Organic Floating Gate Memory Structures 127
4.1 Introduction 127
4.1.1 Organic Non-volatile Memory Devices 128
4.1.1.1 Floating Gate Memories 129
4.1.1.2 Embedded MIM Structures 131
4.2 Organic Metal-Insulator-Semiconductor (OMIS) Memory Structures 133
4.2.1 OMIS Memory Devices with Thin Layer of Au as Floating Gate 134
4.2.2 OMIS Memory Devices with AuNPs as Floating Gate 136
4.2.3 OMIS Memory Devices with SWCNTs as Floating Gate 138
4.3 Organic Thin Film Memory Transistors (OTFMTs) 140
4.3.1 OTFMTs with Thin Layer of Au and AuNPs as Floating Gates 140
4.3.2 OTFMTs with SWCNTs as Floating Gate 147
4.4 SWCNTs as Charge Traps in MIM Memory Structure 152
Acknowledgments 157
References 157
5 Nanoparticles-Based Flash-Like Nonvolatile Memories: Cluster Beam Synthesis of Metallic Nanoparticles and Challenges for the Overlying Control Oxide Layer 161
5.1 Introduction 161
5.2 Cluster Beam Generation of Metallic NPs 162
5.2.1 Cluster Beam Synthesis of NPs Films 164
5.3 Dielectrics for NVM 168
5.3.1 Trapping Properties of HfO2 High-k Dielectric Films 168
5.3.2 Optimization of the HfO2 High-k Dielectric Film 175
5.3.3 Leakage Current of HfO2 High-k Dielectric Films 180
5.3.3.1 Trap-Free Sample 183
5.3.3.2 Charge-Trap Sample 186
5.4 Use of Metallic NPs for Flash-like NVM Applications 188
5.4.1 Ni NPs Prototypes 189
5.4.2 Pt NPs Prototypes 196
5.4.2.1 Samples A1 and A2 (6 nm NPs) 197
5.4.2.2 Samples B1 and B2 (2 nm NPs) 198
5.4.3 Au NPs Prototypes 201
5.5 Comparison of Flash-like NVMs Based on Metallic NPs 209
References 211
Index 215