Switching kinetics of memristive devices employing topotactic brownmillerite-perovskite phase transitions (MEMTOP)

采用拓扑棕针矿-钙钛矿相变的忆阻器件的开关动力学 (MEMTOP)

• 批准号: 505655178
• 负责人: Professor Roger De Souza, Ph.D.
• 金额: --
• 依托单位: PGI-7: Elektronische Materialien
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/505655178?language=en
• 关键词: Switching; kinetics; memristive; devices; employing

Redox-based memristive devices are highly attractive candidates for future non-volatile memories and for artificial synapses in neuromorphic circuits. The memristive behavior is usually induced by the field-driven movement of oxygen ions leading to a local nanoscale redox reaction. In thin films of certain perovskites, such as manganites, ferrites and cobaltites, this redox process results in a topotactic phase transition between a conducting perovskite (PV) phase with disordered oxygen vacancies and an insulating brownmillerite (BM) phase with ordered oxygen vacancies. In such cases, the oxygen-ion transport kinetics are expected to determine the memristive device’s performance, in terms of switching speed, retention and plasticity of artificial synapses, but at present these ion transport kinetics are poorly understood. It is only known that resistive switching in BM films strongly depends on the orientation of the BM thin film. In this project, we will combine a variety of experimental and computational techniques to elucidate the relationship between the orientation-dependent oxygen-ion transport in cobaltite and ferrite BM thin films and the switching kinetics of the corresponding memristive devices. Specifically, we will develop fabrication routes for different crystal orientations for two different deposition techniques, pulsed laser deposition (PLD) and metal-organic chemical vapour deposition (MOCVD). Such samples will be subjected, on the one hand, to in situ X-ray diffraction (XRD) and in situ Raman spectroscopy to monitor the dynamics of the topotatic phase transition, and on the other hand, to 18O isotope exchange anneals and subsequent secondary ion mass spectrometry (SIMS) or Raman spectroscopy analysis to obtain tracer diffusion coefficients of oxygen in both PV and BM thin films. Both branches of these studies will be supported by molecular dynamics (MD) simulations. In this way, we aim to link the kinetics of the topotactic phase transition to the oxygen-ion transport kinetics along different crystalline directions. The third stage consists of elucidating the switching mechanism and the kinetics of BM memristive devices with different crystalline orientations by means of different operando switching techniques. Putting all the gained knowledge on topotactic phase transitions together, we will derive design rules for memristive devices with improved switching kinetics.

基于氧化还原的忆阻器件是未来非易失性存储器和神经形态电路中的人工突触的非常有吸引力的候选者。忆阻行为通常由导致局部纳米级氧化还原反应的氧离子的场驱动运动引起。在某些钙钛矿如锰氧化物、铁氧体和钴矿的薄膜中，该氧化还原过程导致具有无序氧空位的导电钙钛矿（PV）相和具有有序氧空位的绝缘棕钙钛矿（BM）相之间的拓扑结构相变。在这种情况下，氧离子传输动力学预计将决定忆阻器件的性能，在人工突触的切换速度，保留和可塑性方面，但目前这些离子传输动力学知之甚少。只知道BM膜中的阻变强烈地依赖于BM薄膜的取向。在这个项目中，我们将联合收割机的各种实验和计算技术来阐明钴酸盐和铁氧体BM薄膜中的取向依赖的氧离子输运和相应的忆阻器件的开关动力学之间的关系。具体来说，我们将开发两种不同的沉积技术，脉冲激光沉积（PLD）和金属有机化学气相沉积（MOCVD）的不同晶体取向的制造路线。这样的样品将受到，一方面，在原位X射线衍射（XRD）和在原位拉曼光谱监测拓扑相变的动力学，另一方面，18 O同位素交换退火和随后的二次离子质谱（西姆斯）或拉曼光谱分析，以获得示踪剂的PV和BM薄膜中的氧扩散系数。这些研究的两个分支都将得到分子动力学（MD）模拟的支持。通过这种方式，我们的目标是链接的拓扑相转变的动力学的氧离子传输动力学沿着不同的结晶方向。第三阶段包括阐明开关机制和动力学的BM忆阻器件具有不同的晶体取向，通过不同的操作开关技术。把所有获得的知识拓扑结构相变在一起，我们将获得设计规则的忆阻器件与改进的开关动力学。