Theoretical study of oxygen in silicon: Breaking of the SiSi bond

Abstract
We present total-energy calculations of finite clusters of silicon atoms in the presence of atomic oxygen. In the calculation we allow atomic relaxation to determine the equilibrium local configuration of atoms. The results show how oxygen breaks the covalent silicon-silicon bond forming a local configuration similar to that of SiO2. This breaking mechanism is essential to understand the oxygen uptake in the process of the oxidation of silicon.