Probability of atomic or molecular oxygen species in silicon and silicon dioxide

Quantum chemical calculations were performed to investigate the probabilities of the existence of molecular and atomic oxygen inside Si and SiO2. Optimized configurations were obtained for both Si and SiO2 clusters including an O-2 molecule or an O atom in the spin singlet or triplet state. The spin triplet O-2 molecule is the most favorable in SiO2, while the spin singlet 0 atom is dominant in Si. The diffusion of an O-2 molecule from the outside to the inside Of SiO2 Was computed with its potential energy change. The dissociation reaction of an O-2 molecule at the SiO2/Si interface and the transfer reaction of an O atom across the SiO2/Si interface were also examined by estimating for their energy barriers.