Efects of Low‑Temperature GeSn Bufer Layers on Sn Surface Segregation During GeSn Epitaxial Growth

We investigate the efects of the low-temperature (LT) GeSn bufer layers on Sn surface segregation during the growth of the additional GeSn layers. Sn surface segregation was observed in the GeSn layers formed on Si substrates at the growth temperature of 300 °C. However, there was no Sn surface segregation in the GeSn layers grown at 300 °C on the LT GeSn bufer layers formed at 225 °C. The Sn surface segregation was limited by the efects of the LT bufer layers. Crystallinity of the GeSn layers grown at 300 °C on the LT GeSn bufer layers was investigated by Raman spectroscopy. The full width at half maximum of the Ge–Ge Raman spectrum obtained from the GeSn layers was about 3.1 cm−1, which means that the formed GeSn layers have excellent crystallinity. We have successfully demonstrated that the LT GeSn bufer layers can limit the Sn surface segregation, which increases the growth temperature and improves crystallinity of the GeSn layers. KCI Citation Count: 5