Abstract: Amorphous structures of germanium-tin (GeSn) thin films as well as their recrystallization processes during thermal annealing were examined by means of transmission electron microscopy. The specimens were prepared by radio-frequency magnetron sputtering. The as-sputtered GeSn thin films possessed an amorphous structure with 16.4 at.%Sn. The specimen crystallized at 325 °C, and Sn atoms were substitutionally incorporated in a diamond structure. The Sn atoms were ejected from Ge at 350 °C, and molten Sn were formed. In the cooling process, it was confirmed that the molten Sn remained at 150 oC which is much lower than the eutectic temperature of the Ge-Sn binary system. Finally, a remarkable Sn precipitates were formed at room temperature.
Authors: Masashi Higashiyama, Manabu Ishimaru, Masayuki Okugawa, and Ryusuke Nakamura
Keywords: Germanium-tin, Amorphou s, Recrystallization, In situ observation