Precipitation of Cu, Ni, and Fe on Frank-type partial dislocations in Czochralski-grown silicon

The segregation behavior of metallic impurities, Cu, Ni, and Fe on Frank-type partial dislocations in Czochalski-grown silicon depends not only on the species of impurities, but also significantly on the cooling rate of the specimen after contamination. In slowly cooled specimens, Cu develops precipitate colonies in the region away from Frank partials and does not decorate them even on an atomic scale, while Ni decorates Frank partials weakly. A high density of Cu or Ni precipitates is observed on Frank partials when specimens are cooled fast. Fe decorates Frank partials both in fast and slowly cooled specimens. The amount of precipitated Fe on Frank partials is larger in a slowly cooled specimen than in a fast cooled one. The difference in segregation behavior on Frank partials among Cu, Ni, and Fe is reasonably interpreted in terms of three parameters: precipitate nuclei as influenced by the dislocation-core structure, crystal structure of precipitates, and diffusivity of impurities in Si.