GE SI HETEROSTRUCTURES GROWN BY SN-SURFACTANT-MEDIATED MOLECULAR-BEAMEPITAXY/

Ge/Si heterostructures were grown on Si (001) by Sn-submonolayer-media ted molecular beam epitaxy (MBE) and characterized by a variety of tec hniques, in order to study the behavior of Sn surfactant during Ge and Si growth and its influence on Ge/Si interface quality. It was found that Sn strongly segregates to the growing surface of both Ge and Si a nd that the presence of Sn surfactant can effectively suppress Ge segr egation into a Si overlayer and enhance the surface mobility of adatom s. These results suggest that Sn-mediated epitaxy can be used as a via ble method to produce Ge/Si superlattices, with an interface quality s uperior to those grown either by conventional MBE or with other types of surfactants. (C) 1995 American Vacuum Society.