Abstract

We investigate the effects of the low-temperature (LT) GeSn buffer 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 buffer layers formed at 225 °C. The Sn surface segregation was limited by the effects of the LT buffer layers. Crystallinity of the GeSn layers grown at 300 °C on the LT GeSn buffer 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 buffer layers can limit the Sn surface segregation, which increases the growth temperature and improves crystallinity of the GeSn layers.

Graphic Abstract

抽象的

我们研究了额外的GeSn层生长过程中低温（LT）GeSn缓冲层对Sn表面偏析的影响。在300℃的生长温度下，在Si衬底上形成的GeSn层中观察到Sn表面偏析。但是，在225°C下形成的LT GeSn缓冲层上，在300°C下生长的GeSn层中没有锡表面偏析。Sn表面的偏析受到LT缓冲层的作用的限制。通过拉曼光谱研究了在LT GeSn缓冲层上于300°C生长的GeSn层的结晶度。从GeSn层获得的Ge–Ge拉曼光谱的半峰全宽约为3.1 cm ^-1，这意味着形成的GeSn层具有优异的结晶度。我们已经成功地证明了LT GeSn缓冲层可以限制Sn表面的偏析，从而提高了生长温度并提高了GeSn层的结晶度。

图形摘要