R&D: High Speed and Reliability Phase Transition Via Constrained Crystallization in Ultrathin a-C/Sb2Te Multilayer Nanostructures

Applied Physics Letters has published an article written by Chentao Zou, College of Science, Donghua University, Shanghai 201620, China, Liangcai Wu, College of Science, Donghua University, Shanghai 201620, China, and National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China, Peng Xu; College of Science, Donghua University, Shanghai 201620, China, Xiaolin Liu; College of Science, Donghua University, Shanghai 201620, China, Yanping Sui; Yuan Xue; Zhitang Song; and Sannian Song, National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.

Abstract: “Operation speed, data retention, thickness variation, and resistance drift are main shortages for conventional Ge₂Sb₂Te₅ based phase change memory (PCM). In this Letter, we propose a type of ultrathin amorphous carbon (a-C)/Sb₂Te multilayer nanostructures with semiconductor process compatibility, which has high speed and excellent reliability in terms of data retention (131 °C for 10-year), thickness variation (1.52%), and resistance drift (0.0095). The PCM devices based on [a-C (1 nm)/Sb₂Te (7 nm)]₅ multilayer nanostructures exhibit a fast operation speed of 5 ns. The SET/RESET resistance ratio remains constant over 10⁵ cycles by more than two orders of magnitude. The excellent performance of a-C/Sb₂Te multilayer nanostructures makes it a promising storage medium to expand the applications of PCM, such as automotive electronics.“