Investigation on pseudo-binary ZnSb–Sb2Te3 material for phase change memory application

Abstract

Crystallization process and amorphous state stability of pseudobinary ZnSb–Sb2Te3 materials have been studied for application in phase change memory. The effects of Zn concentration and Sb content on crystalline resistance, crystallization temperature, crystallization activation energy and amorphous state stability of films have been studied. The microstructures of Sb-rich Zn–Sb–Te films were analyzed through X-ray diffraction. Different crystalline phases have been observed in annealed Sb-rich Zn–Sb–Te films. Low Zn-doping concentration Zn–Sb–Te films crystallized into rhombohedral Sb2Te3 phase while high Zn-doping concentration Zn–Sb–Te films crystallized into rhombohedral Sb phase. The crystallization activation energy (Ea) of Zn1.1Sb45.7Te53.2 and Zn5.2Sb46.3Te48.5 films were confirmed to be 2.0 and 2.93eV, while Ea of Zn16.0Sb47.3Te36.7 film increased to 3.2eV and further reached to 3.3eV for Zn19.7Sb48.1Te32.2 film. Zn addition increased the crystallization temperature and crystalline resistance of Zn–Sb–Te films largely, and enhanced the amorphous thermal stability and data retention ability of the films, while high Sb/Te ratio reveals the improvement in crystallization speed and good cycle ability. Therefore, Sb-rich Zn–Sb–Te film seems to be a good way to solve the contradiction between thermal stability and fast crystallization speed.