Metal‐oxide‐based bipolar resistive switching (BRS) redox‐based resistive switching memory (ReRAM) shows many outstanding properties making it of interest as an emerging nonvolatile memory. However, it often suffers from a low R_OFF/R_ON ratio, while a large ratio is desired to compensate for read margin loss due to the intrinsic variability of the ReRAM cells. Understanding of the physical processes responsible for limitations of the R_OFF and R_ON in ReRAM cells is therefore of high importance. In this paper a study on the RESET process in BRS Ta₂O₅‐based ReRAM cells is presented. The R_OFF is found to be limited by a secondary volatile resistive switching mode that shows an opposite polarity compared to the main BRS mode. Based on results of switching kinetics measurements a physical model is proposed. It involves an oxygen exchange reaction at the metal‐oxide/active electrode interface combined with a drift‐diffusion induced migration of the resulting oxygen vacancy defects within the metal‐oxide. Incorporation of a thin oxygen‐blocking layer at the active interface allows for a suppression of the secondary switching mechanism. The improved RESET characteristic results in a strongly increased maximum R_OFF. These results provide new insights into the role of the electrode material on the RESET process in BRS ReRAM cells.

中文翻译：

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电极材料对氧化物ReRAM器件中RESET限制的作用

基于金属氧化物的双极电阻式开关（BRS）基于氧化还原的电阻式开关存储器（ReRAM）具有许多出色的性能，使其成为新兴的非易失性存储器。然而，它经常遭受低的R _OFF / R _ON比率的困扰，而由于ReRAM单元的固有可变性，需要大的比率来补偿读取裕量损失。因此，了解负责限制ReRAM单元中R _OFF和R _ON的物理过程非常重要。在本文中，对基于BRS Ta ₂ O ₅的ReRAM单元中的RESET过程进行了研究。在[R _OFF被发现受次级挥发性电阻开关模式的限制，该次级挥发性电阻开关模式与主BRS模式相比具有相反的极性。基于转换动力学测量的结果，提出了一个物理模型。它涉及金属-氧化物/活性电极界面处的氧交换反应，以及漂移扩散引起的金属-氧化物内部氧空位缺陷的迁移。在主动界面处加入一个薄的氧气阻挡层可以抑制次级开关机制。改善的RESET特性会导致最大R _OFF大大增加。这些结果为BRS ReRAM单元中电极材料在RESET过程中的作用提供了新的见解。