Impact of the size 4 cluster on low temperature indium diffusion in silicon

Using ab initio density functional theory the configuration space of indium clusters in silicon up to size 4 is explored. The strongest binding energy corresponds to a cluster containing one indium and three self-interstitials. Two plausible configurations almost degenerate in energy are found: the <100> I4 model and an alternative which combines two <110> split di-interstitials. The segregation of indium to a InI4 cluster is found to capture the dual peak and the low temperature annealing behaviour of indium