R&D: Multilevel Optoelectronic Hybrid Memory Based on N Boped Ge2Sb2Te5 Film with Low Resistance Drift and Ultrafast Speed

Chinese Physics B has published an article written by Ben Wu, Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China, Tao Wei, Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China, and State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China, Jing Hu, Ruirui Wang, Qianqian Liu, Miao Cheng, Wanfei Li, Yun Ling, Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China, and Bo Liu, Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China, and State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.

Abstract: “Multilevel phase-change memory is an attractive technology to increase storage capacity and density owing to its high-speed, scalable and non-volatile characteristics. However, the contradiction between thermal stability and operation speed is one of key factors to restrain the development of phase-change memory. Here, N doped Ge₂Sb₂Te₅ based optoelectronic hybrid memory is proposed to simultaneously implement high thermal stability and ultrafast operation speed. The picosecond laser is adopted to write/erase information based on reversible phase transition characteristics whereas the resistance is detected to perform information readout. Results show that when N content is 27.4 at. %, N-doped Ge₂Sb₂Te₅ film possesses high ten-year data retention temperature of 175 ℃ and low resistance drift coefficient of 0.00024 at 85 ℃, 0.00170 at 120 ℃, and 0.00249 at 150 ℃, respectively, owing to the formation of Ge-N, Sb-N and Te-N bonds. The SET/RESET operation speeds of the film reach 520 ps/13 ps. In parallel, the reversible switching cycle of corresponding device is realized with the resistance ratio of three orders of magnitude. Four-level reversible resistance states induced by various crystallization degrees are also obtained together with low resistance drift coefficients. Therefore, N doped Ge₂Sb₂Te₅ thin film is a promising phase-change material for ultrafast multilevel optoelectronic hybrid storage.“