Optoelectronic Hybrid Phase Change Memory with Excellent Operation Speed and Thermal Stability Based on N-Doped Sb4te Thin Film

Abstract

Non-volatile phase change memory can simultaneously store data and compute in memory, which is beneficial for the breakthrough of “memory bottleneck”. However, its operation speed and thermal stability are difficult to simultaneously meet the requirements of in-memory computing, especially in high-temperature applications. This work proposes an optoelectronic hybrid phase change memory based on N doped Sb4Te material. Results show that N doped Sb4Te thin film with N concentration of 4.73 at. % has the crystallization temperature of 207.1 °C, ten-year data-retention temperature of 156.9 °C, a low density-change rate (0.5%), and small resistance drift coefficient (0.06 @ 85 °C, 0.12 @ 125 °C and 0.18 @ 150 °C). The corresponding memory device cell has the SET/RESET operation speeds of as fast as 52 ps/13 ps, together with the RESET/SET resistance ratio of higher than two orders of magnitude. Structural analysis indicates that nitrogen can enter lattice interstices to suppress grain growth and reduce grain size, thus enhancing thermal stability of amorphous thin film, while its polyhedral structure based on Sb groups ensures ultrafast phase change. Therefore, N doped Sb4Te based optoelectronic hybrid phase change memory with superior thermal stability and operation speed may provide a potential solution for computing in memory.

Keywords: Optoelectronic hybrid phase change memory, N doped Sb4Te thin film, Thermal stability, operation speed