Towards Si-Cap-Free SiGe Passivation: Impact of Surface Preparation on Low-Pressure Oxidation of SiGe

The steam oxidation of SiGe shows a transition from Si-like to Ge-like oxidation behavior depending on Ge concentration and oxidation temperature. Ge-like oxidation is described by the generation of oxygen vacancies (VO) at the interface between the oxide and SiGe virtual substrate. [1] Due to the different oxidation behavior, the presence of a Ge-oxide-free interfacial layer (IL) can suppress SiGe oxidation. [2] Here we show how a passivating interfacial layer can be grown using low-pressure oxidation and highlight the importance of SiGe surface preparation prior to low-pressure oxidation.