Copper related diffusion phenomena in germanium and silicon

This paper concerns diffusion related properties of Cu in Ge and Si. In Ge, Cu prefers to occupy a substitutional lattice site whereas Cu in Si is mainly dissolved on an interstitial position. This difference in the lattice site occupancy is also reflected in the diffusion behaviour. Whereas Cu diffusion in Ge is accurately described on the basis of the dissociative mechanism, which involves Ge vacancies for the conversion of Cu from interstitial to substitutional sites, the diffusion of Cu in Si is mainly mediated by the direct interstitial mechanism. The specific diffusion behaviour of Cu in Ge and Si as well as its electronic properties strongly affect other diffusion related phenomena such as the precipitation and gettering of Cu. Detailed understanding of the latter processes are of fundamental technological significance to keep the contamination of electronic devices during processing to a harmless level. The various aspects of Cu in Ge and Si, which are the result of former and recent experiments, are reviewed in this paper. (C) 2004 Elsevier Ltd. All rights reserved.