Suppression of Interfacial Mixing by Sb Deposition in Si/Ge Strained-Layer Superlattices

Abstract

We have studied interfacial mixing of Si/Ge strained-layer superlattices during Si molecular beam epitaxy. The mixing has been shown to be primarily due to the surface segregation of Ge atoms during Si overlayer growth. It has been found that only the Ge atoms on the topmost Ge layer dominantly segregate to the growing surface. It has also been found that the surface segregation of Ge is effectively suppressed by depositing Sb atoms on the Ge layers. It has been demonstrated that Si/Ge superlattices with abrupt Si/Ge interfaces can be grown by depositing Sb. The two state exchange model is used to discuss the surface segregation of Ge and the suppression of the segregation by Sb deposition.