Modeling and characterization of atomically sharp “perfect” Ge/SiO2 interfaces

We have shown that oxidation of germanium-implanted Si can produce a pile-up of Ge in front of the oxidation front and produce an atomically-sharp interface. In this paper, we examine band-structure and processing of such an interface. Based on ab-initio calculations, the band structure of the sharp interface seems to be more favorable for use in electronic devices than the usually diffuse interface in Si/SiO2. Furthermore, we propose an ab-initio based Monte-Carlo model to simulate oxidation of SiGe alloys. The model explains the formation of the sharp interface due to the repulsive interaction between O and Ge. Furthermore, inclusion of Ge into the oxide is predicted for higher Ge concentrations, in agreement with experiment.