Examinations were made of diffusion mechanisms of the vacancy-O complex (VO) in bulk Si, by using ab initio calculations based upon a 64-atom super-cell. Two atomic mechanisms were found to be involved in VO diffusion. One was caused by the migration of an interstitial O atom; the other by the migration of a vacancy. The energy barrier of the mechanism due to O migration was 2.02eV, and that caused by vacancy migration was 1.98eV. These energy barriers were close to the experimental activation energy of 2.0eV; required for the dissociation and diffusion of VO. The derived activation energies of the 2 mechanisms suggested that these mechanisms might occur simultaneously. It was clarified that the dissociation energy (1.85eV) of VO was lower than the diffusion energy of VO.

Diffusion and Dissociation Mechanisms of Vacancy-Oxygen Complex in Silicon. M.Furuhashi, K.Taniguchi: Applied Physics Letters, 2005, 86[14], 142107