Realization of Selector‐Memory Bi‐Functionality with Self‐Current Regulation Utilizing Poly‐Crystalline Based GST Electrolyte for Memristor Hardware Development

Abstract

Abstract Conductive bridge random‐access memory (CBRAM) are two terminal devices that offer excellent switching performance. In addition, CBRAM shows various switching modes, including volatile threshold switching (TS) and nonvolatile threshold switching (N‐TS). These properties expand its applications to memory, selector, biological synapses, and neurons. However, due to the uncontrollable behavior of stochastic switching between TS and N‐TS in CBRAM devices, a novel approach is needed to improve the switching performance of CBRAM. Moreover, conventional devices that have different stacking between TS and N‐TS increase fabrication cost and worsen the device yield. Here, the selector‐memory bi‐functionality with self‐current regulation effect of Ag‐inserted Ge2Sb2Te5 (GST) thin films is demonstrated. Selector‐memory bi‐functionality, having TS behavior with an adjustable on/off current, with confined conductive filaments (CFs) improves the uniformity and reduces the fabrication cost by implementing TS/N‐TS in a single stack. From the material analysis, it becomes evident that confined Ag‐based CFs within GST films are key factors for realizing selector‐memory bi‐functionality. The selector‐memory bi‐functionality is achieved through the reaction of Ag metal cations with non‐bonded Te atoms in GST film depending on field polarity. These results suggest that the Ag‐inserted GST film contributes to the development of large‐scale nonvolatile memory and neuromorphic application.

Keywords

• conductive bridge memory
• memory
• phase change memory
• selector
• selector‐memory bi‐functionality