Influence of Sn Migration on phase transition in GeTe and Ge₂ Se₃ thin films

Phase transitions in GeTe/SnSe and Ge₂ Se₃ /SnTe are investigated using time resolved x-ray diffraction. GeTe exhibits a structural transition from rhombohedral to the cubic phase at 300 °C, which is ∼100 °C lower than that of pure GeTe. This is facilitated by incorporation of Sn from SnSe. Sn migration is observed explicitly in Ge₂ Se₃ /SnTe by separation of SnSe phase. Amorphous Ge₂ Se₃ is also found to crystallize at a lower temperature of 300 °C resulting in orthorhombic GeSe and monoclinic GeSe₂. Thus, inclusion of a Sn containing layer may offer a means to tailor phase transition in Ge-chalcogenide thin films for phase change memory applications.