Crystallization processes of Sb100−xZnx (0 ≤ x ≤ 70) amorphous films for use as phase change memory materials

Abstract

The phase change processes of as-deposited Sb-Zn films were investigated. The as-deposited amorphous SbZn film showed an unusual increase in resistance during heating, which was attributed to crystallization of the metastable SbZn phase. Further heating up to more than 300oC resulted in a structural transformation into the stable SbZn phase accompanied by a drop in resistance as in conventional phase change materials. Even though off-stoichiometric Sb-rich films exhibited crystallization into the metastable phase as well, the precipitation of Sb crystalline grains caused an undesirable drop in resistance at temperatures lower than that of the SbZn film. A memory device using an SbZn film showed typical switching behavior and successfully switched from the amorphous to crystal state and vice versa by the application of an electric pulse. These results revealed that stoichiometric SbZn film is a promising novel phase change material for phase change memory with high thermal stability.