Mechanisms were found for enhanced O diffusion. Such diffusion proceeded via the migration of O dimers. The calculated activation energy was 1.5eV, which was close to the experimental estimate (1.7eV) for the activation energy of thermal donor formation. It was therefore concluded that the formation of thermal donors occurred via the migration of O dimers, and that H-enhanced O diffusion occurred via migration of the O-H complex. The calculated activation energy for diffusion was about 1.2eV, and was again in good agreement with experimental data. In each case, a reduction in the diffusion activation energy, of about 1.0eV, as compared with the 2.5eV activation energy for the isolated O atom, was attributed to the saturation of a dangling bond on one of the principal Si atoms during migration.

Enhanced Modes of Oxygen Diffusion in Silicon. M.Ramamoorthy, S.T.Pantelides: Solid State Communications, 1998, 106[5], 243-8