The recent co-optimization of memristive technologies and programming algorithms enabled neural networks training with in-memory computing systems. In this context, novel analog filamentary conductive-metal-oxide (CMO)/HfO_x redox-based resistive switching memory (ReRAM) represents a key technology. Despite device performance enhancements reported in literature, the underlying mechanism behind resistive switching is not fully understood. This work presents the first physics-based analytical model of the current transport and of the resistive switching in these devices. As a case study, analog TaO_x/HfO_x ReRAM devices are considered. The current transport is explained by a trap-to-trap tunneling process, and the resistive switching by a modulation of the defect density within the sub-band of the TaO_x that behaves as electric field and temperature confinement layer. The local temperature and electric field distributions are derived from the solution of the electric and heat transport equations in a 3D finite element ReRAM model. The intermediate resistive states are described as a gradual modulation of the TaO_x defect density, which results in a variation of its electrical conductivity. The drift-dynamics of ions during the resistive switching is analytically described, allowing the estimation of defect migration energies in the TaO_x layer. Moreover, the role of the electro-thermal properties of the CMO layer is unveiled. The proposed analytical model accurately describes the experimental switching characteristic of analog TaO_x/HfO_x ReRAM devices, increasing the physical understanding and providing the equations necessary for circuit simulations incorporating this technology.

中文翻译：

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模拟丝状导电金属氧化物/HfOx ReRAM 器件传输的分析建模

最近忆阻技术和编程算法的共同优化使得神经网络能够通过内存计算系统进行训练。在此背景下，新型模拟丝状导电金属氧化物（CMO）/基于HfO _x氧化还原的电阻开关存储器（ReRAM）代表了一项关键技术。尽管文献中报道了器件性能的增强，但电阻开关背后的基本机制尚未完全了解。这项工作提出了第一个基于物理的电流传输和这些设备中的电阻开关的分析模型。作为案例研究，我们考虑模拟 TaO _x /HfO _x ReRAM 器件。电流传输可以通过陷阱到陷阱的隧道过程来解释，电阻切换可以通过调节 TaO _x子带内的缺陷密度来解释，TaO x 充当电场和温度限制层。局部温度和电场分布是通过 3D 有限元 ReRAM 模型中的电和热传输方程的解得出的。中间电阻态被描述为 TaO _x缺陷密度的逐渐调制，这导致其电导率的变化。分析描述了电阻切换过程中离子的漂移动力学，从而可以估计 TaO _x层中的缺陷迁移能量。此外，CMO 层的电热特性的作用也被揭示。所提出的分析模型准确地描述了模拟 TaO _x /HfO _x ReRAM 器件的实验开关特性，增加了物理理解并提供了结合该技术的电路仿真所需的方程。