Resistive random-access memory (RRAM) devices have attracted broad interest as promising building blocks for high-density nonvolatile memory and neuromorphic computing applications. Atomic level thermodynamic and kinetic descriptions of resistive switching (RS) processes are essential for continued device design and optimization but are relatively lacking for oxide-based RRAMs. It is generally accepted that RS occurs due to the redistribution of charged oxygen vacancies driven by an external electric field. However, this assumption contradicts the experimentally observed stable filaments, where the high vacancy concentration should lead to a strong Coulomb repulsion and filament instability. In this work, through predictive atomistic calculations in combination with experimental measurements, we attempt to understand the interactions between oxygen vacancies and the microscopic processes that are required for stable RS in a Ta₂O₅-based RRAM. We propose a model based on a series of charge transition processes that explains the drift and aggregation of vacancies during RS. The model was validated by experimental measurements where illuminated devices exhibit accelerated RS behaviors during SET and RESET. The activation energies of ion migration and charge transition were further experimentally determined through a transient current measurement, consistent with the modeling results. Our results help provide comprehensive understanding on the internal dynamics of RS and will benefit device optimization and applications.

中文翻译：

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基于氧化物的RRAM电阻切换过程中氧空位的电荷跃迁

作为高密度非易失性存储器和神经形态计算应用程序的有前途的构建块，电阻式随机存取存储器（RRAM）器件引起了广泛的兴趣。电阻转换（RS）过程的原子级热力学和动力学描述对于继续进行器件设计和优化至关重要，但对于基于氧化物的RRAM则相对缺乏。通常认为，RS的产生是由于外部电场驱动的带电氧空位的重新分布。然而，该假设与实验观察到的稳定的长丝相矛盾，在那里高的空位浓度应导致强烈的库仑排斥力和长丝不稳定性。在这项工作中，通过预测性原子计算结合实验测量，基于₂ O ₅的RRAM。我们提出了基于一系列电荷转移过程的模型，该模型解释了RS期间空位的漂移和聚集。通过实验测量验证了该模型，其中，照明设备在SET和RESET期间表现出加速的RS行为。离子迁移和电荷跃迁的活化能通过瞬态电流测量进一步通过实验确定，与建模结果一致。我们的结果有助于全面了解RS的内部动态，并将有助于设备优化和应用。