Zhang Yewei, Wang Chaolun, Wu Xing
In Situ Devices Center, School of Communication and Electronic Engineering, East China Normal University, Shanghai 200241, China.
Nanoscale. 2022 Jul 14;14(27):9542-9552. doi: 10.1039/d2nr01872a.
Resistive random access memory (RRAM) devices have been demonstrated to be a promising solution for the implementation of a neuromorphic system with high-density synapses due to the simple device structure, nanoscale dimension, high switching speed, and low power consumption. Various electrical stimuli applied to RRAM devices could cause various working modes of the bionic synapses. The application of RRAM devices needs to understand the micromechanism of the resistive switching process, which is inseparable from advanced characterization techniques. transmission electron microscopy (TEM) with high-resolution imaging and versatile external fields plays an important role in the static characterization and dynamic manipulation of nanoscale devices. Focused on TEM techniques, this review article introduces TEM setups and the corresponding sample fabrication process for RRAM research. Then, the electrical stimulating methodologies including pulse and direct current voltage applied to RRAM are introduced, followed by the summary of electron holography to characterize the electrical potential distribution. By applying various electrical stimuli to the RRAM samples, the working mode of bionic synapses could be changed according to the requirement. Finally, the outlook of the RRAM study with TEM is proposed. This review demonstrates the electrical stimulus capability of TEM to understand the physical mechanism of various types of RRAM devices.
电阻式随机存取存储器（RRAM）器件因其简单的器件结构、纳米级尺寸、高开关速度和低功耗，已被证明是实现具有高密度突触的神经形态系统的一种有前景的解决方案。施加到RRAM器件上的各种电刺激可导致仿生突触的各种工作模式。RRAM器件的应用需要了解电阻开关过程的微观机制，这离不开先进的表征技术。具有高分辨率成像和多功能外部场的透射电子显微镜（TEM）在纳米级器件的静态表征和动态操纵中起着重要作用。围绕TEM技术，本文综述介绍了用于RRAM研究的TEM装置和相应的样品制备过程。然后，介绍了施加到RRAM上的包括脉冲和直流电压在内的电刺激方法，接着总结了用于表征电势分布的电子全息术。通过对RRAM样品施加各种电刺激，可以根据需要改变仿生突触的工作模式。最后，提出了利用TEM进行RRAM研究的展望。本文综述展示了TEM理解各类RRAM器件物理机制的电刺激能力。
