Institut für Werkstoffe der Elektrotechnik 2, RWTH Aachen University, 52074 Aachen, Germany.
ACS Nano. 2013 Jul 23;7(7):6396-402. doi: 10.1021/nn4026614. Epub 2013 Jun 24.
Resistive switching memories (ReRAMs) are the major candidates for replacing the state-of-the-art memory technology in future nanoelectronics. These nonvolatile memory cells are based on nanoionic redox processes and offer prospects for high scalability, ultrafast write and read access, and low power consumption. The interfacial electrochemical reactions of oxidation and reduction of ions necessarily needed for resistive switching result inevitably in nonequilibrium states, which play a fundamental role in the processes involved during device operation. We report on nonequilibrium states in SiO2-based ReRAMs being induced during the resistance transition. It is demonstrated that the formation of metallic cations proceeds in parallel to reduction of moisture, supplied by the ambient. The latter results in the formation of an electromotive force in the range of up to 600 mV. The outcome of the study highlights the hitherto overlooked necessity of a counter charge/reaction to keep the charge electroneutrality in cation-transporting thin films, making it hard to analyze and compare experimental results under different ambient conditions such as water partial pressure. Together with the dependence of the electromotive force on the ambient, these results contribute to the microscopic understanding of the resistive switching phenomena in cation-based ReRAMs.
阻变存储器（ReRAM）是替代未来纳米电子学中最先进存储技术的主要候选者。这些非易失性存储单元基于纳米离子氧化还原过程，具有高可扩展性、超快速写入和读取访问以及低功耗的前景。阻变所需的界面电化学氧化还原反应不可避免地导致非平衡态，这在器件操作过程中涉及的过程中起着根本性的作用。我们报告了在 SiO2 基 ReRAM 中诱导的非平衡态，在电阻转变过程中。结果表明，金属阳离子的形成与环境提供的水分的还原平行进行。后者导致电动势在高达 600 mV 的范围内形成。研究结果强调了迄今为止被忽视的必要性，即在阳离子传输薄膜中需要反电荷/反应来保持电荷电中性，这使得很难在不同环境条件（如分压）下分析和比较实验结果。与环境对电动势的依赖性一起，这些结果有助于对基于阳离子的 ReRAM 中的阻变现象进行微观理解。
