Temperature dependence of structural and optical properties of GeSbTe alloy thin films

Abstract Ge 2 Sb 2 Te 5 films sandwiched by ZnS–SiO 2 layers were studied by spectroscopic ellipsometry from room temperature up to 800°C. An irreversible modification of both materials is pointed out. ZnS cubic phase precipitation occurs after heating at 650°C, shown by grazing incidence X-ray diffraction. Chemical modification in phase change material is observed above 300°C, revealed by a typical behavior of a transparent layer.