The in-diffusion and annealing of substitutional Ni atoms in dislocation-free material were studied at 960C in order to distinguish between site exchange mechanisms for the Ni atoms. The concentration of substitutional Ni atoms varied exponentially with time according to the theory of the dissociative mechanisms for both processes. Interstitial Ni atoms in dislocation-free material precipitated in the bulk; as confirmed by infra-red microscopy. These precipitates played an important role in vacancy generation and annihilation. It was suggested that, in dislocation-free samples, Ni diffused via a dissociative mechanism, that the dominant point defects which mediated the site exchange of Ni atoms were vacancies, and that crystal surfaces and precipitates played a role as sinks and sources for vacancy annihilation and generation. The rate-limiting step for the site-exchange of substitutional Ni atoms was the diffusion of vacancies.

Dissociative Diffusion of Nickel in Silicon, and Sinks and Sources of Vacancy Annihilation and Generation in the Crystal Bulk H.Kitagawa, S.Tanaka: Physica B, 1999, 273-274, 391-4