氧化还原类阻变存储器的机理探讨和性能调控及逻辑应用
发布时间：2019-07-03 18:05
【摘要】：氧化还原类阻变存储器是下一代高速、高密度和低功耗非易失性存储器的有力竞争者,对其机理的探讨、性能的优化和应用的拓展一直以来都倍受科学界和工业界关注。本文采用旋涂法制备了P3HT:PCBM和PEDOT:PSS薄膜,采用射频磁控溅射技术制备了SiO_2和Ta_2O_5薄膜,基于这些薄膜构建了氧化还原类阻变存储器,系统表征了器件的阻变性能,重点探讨了金属导电细丝的生长动力学过程和二元氧化物介质阻变特性的可控调节,并探索了逻辑运算在阻变存储器中的多样化实现途径。选用不同电极材料和存储介质研究了氧化还原类阻变存储器中金属导电细丝的生长动力学过程,成功获得了两种不同于传统的由惰性电极朝向活性电极的金属导电细丝生长模式,即Cu/P3HT:PCBM/ITO器件中由活性电极朝向惰性电极的生长模式和Ag/PEDOT:PSS/Pt器件中由存储介质中间向两端电极逐渐延伸的生长模式。理论分析和计算机模拟表明,金属导电细丝的生长模式同时受阳离子迁移和导电细丝形核两个过程的影响。当阳离子迁移过程起主导作用时,金属导电细丝的生长模式为由活性电极朝向惰性电极;反之,当导电细丝形核过程起主导作用时,金属导电细丝的生长模式为由惰性电极朝向活性电极。当这两个过程相互竞争、共同起作用时,金属导电细丝的生长模式为由存储介质中间向两端电极逐渐延伸。实验还通过优化测试参数以调控金属导电细丝的演化过程,在P3HT:PCBM和SiO_2存储介质中观测到了Ag导电细丝的电导量子化现象。采用n-Si半导体电极和插入超薄的Ta纳米层调控了Ta_2O_5薄膜的阻变特性,成功制备了开关比高达约104倍、整流比高达约600倍的Pt/Ta_2O_5/n-Si自整流阻变存储器,其自整流效应起源于氧空位导电细丝和n-Si半导体电极间的肖特基接触,能够克服最大容量为212×212(约44kbit)的存储阵列的漏电流;成功实现了10nm厚Ta_2O_5薄膜从本征无极性阻变特性到自限流双极性阻变特性(2nm厚Ta插入层时)和互补型阻变特性(4nm厚Ta插入层时)的可控转变,同时降低了操作电压和电流,提高了阻变均一性。为了提升阻变存储器的逻辑运算能力,理论设计和实验证明了一种含有内在可反转二极管的新型互补型阻变存储器,并在单个Ta/Ta_2O_5/Pt/Ta_2O_5/Ta新型互补型阻变存储器中,证实了基于内在可反转二极管和互补型阻变特性分别实现所有16种二元布尔逻辑运算的可行性。
[Abstract]:Redox resistive memory is a powerful competitor for the next generation of high-speed, high-density and low-power non-volatile memory. The discussion on its mechanism, performance optimization and application expansion have always attracted the attention of the scientific community and industry. In this paper, P3HT:PCBM and PEDOT:PSS thin films were prepared by rotating coating method, and SiO_2 and Ta_2O_5 thin films were prepared by RF magnetron sputter. Based on these films, redox resistive memory was constructed. The resistive properties of the devices were systematically characterized. The growth kinetics of metal conductive filaments and the controllable adjustment of resistance characteristics of binary oxide media were discussed. The diversified implementation of logic operation in resistive memory is also explored. The growth kinetics of metal conductive filaments in redox impedance memory was studied by using different electrode materials and storage media. Two kinds of metal conductive filaments growth modes, which were different from the traditional metal conductive filaments from the lazy electrode to the active electrode, were successfully obtained. That is, the growth mode from the active electrode to the lazy electrode in the Cu/P3HT:PCBM/ITO device and the growth mode from the middle of the storage medium to the two ends of the electrode in the Ag/PEDOT:PSS/Pt device. Theoretical analysis and computer simulation show that the growth mode of metal conductive filaments is affected by both cationic migration and conductive filaments nucleation. When the cationic migration process plays a leading role, the growth mode of metal conductive filaments is that the active electrode is oriented to the lazy electrode; on the contrary, when the nucleation process of conductive filaments plays a leading role, the growth mode of metal conductive filaments is that the lazy electrode is oriented to the active electrode. When the two processes compete with each other and work together, the growth mode of metal conductive filaments extends gradually from the middle of the storage medium to the electrodes at both ends. The conductivity quantization of Ag conductive filaments was observed in P3HT:PCBM and SiO_2 storage media by optimizing the test parameters to regulate the evolution of conductive filaments. The resistance characteristics of Ta_2O_5 thin films were regulated by n-Si semiconductor electrode and ultra-thin Ta nanolayer. Pt/Ta_2O_5/n-Si self-rectifying resistive memory with switching ratio of about 104 times and rectifier ratio of about 600 times was successfully fabricated. The self-rectifying effect originated from Schottky contact between oxygen vacancy conductive filaments and n-Si semiconductor electrodes. It can overcome the leakage current of the storage array with a maximum capacity of 212 脳 212 (about 44kbit). The controllable transformation of 10 nm thick Ta _ 2O_5 thin films from intrinsic non-polar resistance to self-limiting current-limiting bipolar resistance (when 2nm thick Ta is inserted into the layer) and complementary resistance (when 4nm thick Ta is inserted into the layer) is successfully realized. At the same time, the operating voltage and current are reduced, and the resistance uniformity is improved. In order to improve the logic operation ability of resistive memory, a new type of complementary resistive memory with intrinsic reversible diode is designed theoretically and experimentally. in a single Ta/Ta_2O_5/Pt/Ta_2O_5/Ta new complementary resistive memory, the feasibility of realizing all 16 binary Boolean logic operations based on intrinsic reversible diode and complementary resistive characteristic is verified.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP333
本文编号：2509576
[Abstract]:Redox resistive memory is a powerful competitor for the next generation of high-speed, high-density and low-power non-volatile memory. The discussion on its mechanism, performance optimization and application expansion have always attracted the attention of the scientific community and industry. In this paper, P3HT:PCBM and PEDOT:PSS thin films were prepared by rotating coating method, and SiO_2 and Ta_2O_5 thin films were prepared by RF magnetron sputter. Based on these films, redox resistive memory was constructed. The resistive properties of the devices were systematically characterized. The growth kinetics of metal conductive filaments and the controllable adjustment of resistance characteristics of binary oxide media were discussed. The diversified implementation of logic operation in resistive memory is also explored. The growth kinetics of metal conductive filaments in redox impedance memory was studied by using different electrode materials and storage media. Two kinds of metal conductive filaments growth modes, which were different from the traditional metal conductive filaments from the lazy electrode to the active electrode, were successfully obtained. That is, the growth mode from the active electrode to the lazy electrode in the Cu/P3HT:PCBM/ITO device and the growth mode from the middle of the storage medium to the two ends of the electrode in the Ag/PEDOT:PSS/Pt device. Theoretical analysis and computer simulation show that the growth mode of metal conductive filaments is affected by both cationic migration and conductive filaments nucleation. When the cationic migration process plays a leading role, the growth mode of metal conductive filaments is that the active electrode is oriented to the lazy electrode; on the contrary, when the nucleation process of conductive filaments plays a leading role, the growth mode of metal conductive filaments is that the lazy electrode is oriented to the active electrode. When the two processes compete with each other and work together, the growth mode of metal conductive filaments extends gradually from the middle of the storage medium to the electrodes at both ends. The conductivity quantization of Ag conductive filaments was observed in P3HT:PCBM and SiO_2 storage media by optimizing the test parameters to regulate the evolution of conductive filaments. The resistance characteristics of Ta_2O_5 thin films were regulated by n-Si semiconductor electrode and ultra-thin Ta nanolayer. Pt/Ta_2O_5/n-Si self-rectifying resistive memory with switching ratio of about 104 times and rectifier ratio of about 600 times was successfully fabricated. The self-rectifying effect originated from Schottky contact between oxygen vacancy conductive filaments and n-Si semiconductor electrodes. It can overcome the leakage current of the storage array with a maximum capacity of 212 脳 212 (about 44kbit). The controllable transformation of 10 nm thick Ta _ 2O_5 thin films from intrinsic non-polar resistance to self-limiting current-limiting bipolar resistance (when 2nm thick Ta is inserted into the layer) and complementary resistance (when 4nm thick Ta is inserted into the layer) is successfully realized. At the same time, the operating voltage and current are reduced, and the resistance uniformity is improved. In order to improve the logic operation ability of resistive memory, a new type of complementary resistive memory with intrinsic reversible diode is designed theoretically and experimentally. in a single Ta/Ta_2O_5/Pt/Ta_2O_5/Ta new complementary resistive memory, the feasibility of realizing all 16 binary Boolean logic operations based on intrinsic reversible diode and complementary resistive characteristic is verified.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP333
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