Electronic structure of substitutional oxygen in silicon

Abstract

The electronic distribution around substitutional oxygen in silicon is calculated. The equilibrium position of oxygen with respect to its neighbouring silicon atoms is obtained via a total energy minimization in finite clusters of atoms. Oxygen is found to be an off-center impurity deviating 0.90 Å in the 〈100〉 direction from the nominal position of the silicon atom it substitutes in agreement with previous models. The Si-O-Si bond formed is similar to that of SiO 2 although the Si-O distance is 1.82 Å instead of 1.61 Å. The two other silicon atoms in the vacancy approach to each other forming a new bond responsible for the experimentally found net acceptor character of the defect.