A general expression for the intrinsic diffusivity of a substitutional impurity was obtained in terms of the self-interstitial and vacancy concentrations. The vacancy mechanism, the exchange mechanism, and 2 processes which were associated with the motion of interstitial impurity atoms (kick-out, Frank-Turnbull) were taken into account. The latter 2 contributions were not additive under non-equilibrium point defect conditions, and could partially cancel in some cases. The general expression could be fitted to As diffusion data which were obtained under nitridation and oxidation conditions. The results indicated the possible presence of appreciable vacancy, push-out, and Frank-Turnbull terms. However, there was no significant exchange term.

N.E.B.Cowern: Journal of Applied Physics, 1988, 64[9], 4484-90