The motion of a substitutional impurity via a fast-diffusing intermediate species was considered. An analytical solution was given for the case of low impurity concentrations. At short times, only a few atoms migrated and the solution behaved exponentially. This exponential signature was observed in the diffusion of nm-scale B-doping profiles. The migration frequency during oxidation-enhanced diffusion was consistent with diffusion-limited kick-out of an interstitial-type B species. This was the first direct experimental evidence for dopant diffusion via an intermediate species.

N.E.B.Cowern, K.T.F.Janssen, G.F.A.Van de Walle, D.J.Gravesteijn: Physical Review Letters, 1990, 65[19], 2434-7