Reversible phase-change characteristics and structural origin in Cr doped Ge_2Sb_2Te_5 thin films

摘要

Phase-change material is the key factor in phase change storage technology, among which Ge2Sb2Te5 (GST) possesses relatively excellent comprehensive performance. In this work, Cr dopants with different concentrations are introduced into GST to further improve the amorphous thermal stability for high-temperature application. The reversible phase-change processes in Cr-doped GST (Cr-GST) films are investigated by femtosecond laser pulses and the structural origin is analyzed. It is found that the thermal stability of Cr-GST film is greatly improved with the increase of Cr-dopants. The 10-year-data retention (T-1(0-year)) of Cr-GST film is higher than 120 degrees C, which is much larger than that of GST and is able to meet the demand of high-temperature applications such as automotive electronics. In SET process, high fluence will probably introduce the competition of melting-quenched amorphization, which may lead to the unexpected decrease of reflectivity. In RESET experiments, the necessary pulse number for amorphization is much fewer and even one pulse is enough at high fluence. The necessary amorphization energy for Cr-GST film with the Cr atom concentration of 10 % is as low as that of GST film, indicating promising application in the fields of high temperature and low power consumption.