Investigation on the stabilization of the median resistance state for phase change memory cell with doublelayer chalcogenide films

摘要

The triple-level data storage capability of the phase change memory with doublelayer chalcogenide films (Sb_2Te_3 and Ge_2Sb_2Te_5) was investigated. Differences in physical properties of these two chalcogenide materials contribute to the appearance of a median resistance state. However, the stable median resistance state can only be achieved by selecting appropriate programming parameters. Voltage pulses with moderate magnitude and pulse width for both set and reset operations are favorable for forming a stable median resistance stage. Interdiffusion between Sb_2Te_3 and Ge_2Sb_2Te_5 layers degrades the stabilization of the median resistance state.