Non-volatile Memories

Pierre Camille Lacaze, Emeritus Professor, Université Denis Diderot, Paris, France. Jean-Christophe?Lacroix, Professor, Université Denis Diderot, Paris, France.

• ACKNOWLEDGEMENTS xiPREFACE xiiiPART 1. INFORMATION STORAGE AND THE STATE OF THE ART OF ELECTRONIC MEMORIES 1CHAPTER 1. GENERAL ISSUES RELATED TO DATA STORAGE AND ANALYSIS CLASSIFICATION OF MEMORIES AND RELATED PERSPECTIVES 31.1. Issues arising from the flow of digital information 31.2. Current electronic memories and their classification 51.3. Memories of the future 8CHAPTER 2. STATE OF THE ART OF DRAM, SRAM, FLASH, HDD AND MRAM ELECTRONIC MEMORIES 132.1. DRAM volatile memories 132.1.1. The operating principle of a MOSFET (metal oxide semiconductor field effect transistor) 142.1.2. Operating characteristics of DRAM memories 172.2. SRAM memories 192.3. Non-volatile memories related to CMOS technology 222.3.1. Operational characteristics of a floating gate MOSFET 222.3.2. Flash memories 382.4. Non-volatile magnetic memories (hard disk drives – HDDs and MRAMs) 452.4.1. The discovery of giant magneto resistance at the origin of the spread of hard disk drives 462.4.2. Spin valves 492.4.3. Magnetic tunnel junctions 512.4.4. Operational characteristics of a hard disk drive (HDD) 512.4.5. Characteristics of a magnetic random access memory (MRAM) 542.5. Conclusion 56CHAPTER 3. EVOLUTION OF SSD TOWARD FERAM, FEFET, CTM AND STT-RAM MEMORIES 593.1. Evolution of DRAMs toward ferroelectric FeRAMs 603.1.1. Characteristics of a ferroelectric material 603.1.2. Principle of an FeRAM memory 633.1.3. Characteristics of an FeFET memory 673.2. The evolution of Flash memories towards charge trap memories (CTM) 773.3. The evolution of magnetic memories (MRAM) toward spin torque transfer memories (STT-RAM) 823.3.1. Nanomagnetism and experimental implications 833.3.2. Characteristics of spin torque transfer 843.3.3. Recent evolution with use of perpendicular magnetic anisotropic materials 883.4. Conclusions 90PART 2. THE EMERGENCE OF NEW CONCEPTS: THE INORGANIC NEMS, PCRAM, RERAM AND ORGANIC MEMORIES 93CHAPTER 4. VOLATILE AND NON-VOLATILE MEMORIES BASED ON NEMS 954.1. Nanoelectromechanical switches with two electrodes 964.1.1. NEMS with cantilevers 974.1.2. NEMS with suspended bridge 1024.1.3. Crossed carbon nanotube networks 1034.2. NEMS switches with three electrodes 1064.2.1. Cantilever switch elaborated by lithographic techniques 1074.2.2. Nanoswitches with carbon nanotubes 1104.2.3. NEMS-FET hybrid memories with a mobile floating gate or mobile cantilever 1164.4. Conclusion 121CHAPTER 5. NON-VOLATILE PHASE-CHANGE ELECTRONIC MEMORIES (PCRAM) 1235.1. Operation of an electronic phase-change memory 1255.1.1. Composition and functioning of a GST PCRAM 1255.1.2. The antinomy between the high resistance of the amorphous state and rapid heating 1295.2. Comparison of physicochemical characteristics of a few phase-change materials 1345.3. Key factors for optimized performances of PCM memories 1375.3.1. Influence of cell geometry on the current Im needed for crystal melting 1385.3.2. Optimization of phase-change alloy composition to improve performance 1435.3.3. Influence of nanostructuration of the phase-change material 1485.3.4. Recent techniques for improvement of amorphization and crystallization rates of phase-change materials 1565.3.5. Problems related to interconnection of PCRAM cells in a 3D crossbar-type architecture 1605.4. Conclusion 162CHAPTER 6. RESISTIVE MEMORY SYSTEMS (RRAM) 1656.1. Main characteristics of resistive memories 1686.1.1. Unipolar system 1696.1.2. Bipolar system 1706.2. Electrochemical metallization memories 1716.2.1. Atomic switches 1746.2.2. Metallization memories with an insulator or a semiconductor 1776.2.3. Conclusions on metallization memories 1826.3. Resistive valence change memories (VCM) 1836.3.1. The first work on resistive memories 1836.3.2. Resistive valence change memories after the 2000s 1856.3.3. A perovskite resistive memory (SrZrO3) with better performance than Flash memories 1866.3.4. Electroforming and resistive switching 1896.3.5. Hafnium oxide for universal resistive memories? 1956.4. Conclusion 198CHAPTER 7. ORGANIC AND NON-VOLATILE ELECTRONIC MEMORIES 2017.1. Flash-type organic memories 2047.1.1. Flexible FG-OFET device with metal floating gate 2057.1.2. Flexible organic FG-OFET entirely elaborated by spin coating and inkjet printing 2127.1.3. Flexible OFETs with charge-trap gate dielectrics 2167.1.4. OFETs with conductive nanoparticles encapsulated in the gate dielectric 2217.1.5. Redox dielectric OFETs 2267.2. Resistive organic memories with two contacts 2307.2.1. Organic memories based on electrochemical metallization 2327.2.2. Resistive charge-trap organic memories 2387.3. Molecular memories 2447.4. Conclusion 248CONCLUSION 251BIBLIOGRAPHY 255INDEX 285