Graphite Carbon-Doped Sb2Te Nanostructures for Phase-Change Memory Applications

Abstract

High thermal stability, fast operation speed, low thickness variation, and low resistance drift of phase-change nanomaterials are the essential characteristics in phase-change memory (PCM) applications. In this work, we put forward a graphite carbon-doped Sb2Te (C-Sb2Te) chalcogenide with semiconductor process compatibility. Our results prove that the proposed C-Sb2Te has excellent thermal stability and high operation speed. More importantly, the thickness change and resistance drift are only 0.89% and 0.0149, respectively. The C-Sb2Te-based memory device exhibits a high switching speed to the instrument test limit (5 ns) with a large resistance ratio, low operation voltage (2 V), and low power consumption (6.9 pJ). The proposed C-Sb2Te nanostructure material exceeds both conventional Ge2Sb2Te5 and transition-metal-doped Sb2Te materials in terms of its performance. Ab initio molecular dynamics simulations reveal that C–C and C–Sb bonds as well as C–C chains are formed in C-Sb2Te, and C doping constrains phase transition in a small region and refines grains of C-Sb2Te, thus resulting in the high performance. Our study suggests that C-Sb2Te is a potential candidate for high-speed, high-thermal-stability, and high-reliability PCM applications.