Realization of Abrupt Interfaces in Si/Ge Superlattices by Suppressing Ge Surface Segregation with Submonolayer of Sb

Atomic mixing in Si/Ge strained-layer superlattices is investigated by means of SIMS and XPS. The interfacial mixing is attributed to the surface segregation of Ge atoms during MBE growth of Si overlayers. It is demonstrated that the surface segregation is remarkably suppressed by depositing submonolayer Sb atoms on Ge layers prior to Si overgrowth and that Ge layers are confined to within 0.8 nm.