A Note on the Theory of Diffusion of Copper in Germanium

The theory of Frank and Turnbull of the diffusion of copper in germanium is extended to take into account the finite rate of generation of vacancies in the bulk, and the finite reaction rate in the postulated dissociation of a substitutional copper atom into an interstitial and a vacancy. Comparison of the extended theory with experiment yields an order of magnitude estimate of 10 -8 cm for the effective radius of a dislocation for annihilation of a vacancy. It is shown that this result is consistent with the view that vacancy generation and annihilation occurs at dislocation jogs, provided that the attraction of an edge dislocation for a vacancy is taken into account.