The Effect of Dislocation Density on the Diffusion of Gold in Thin Silicon Slices

Abstract

The effect of dislocation density on the diffusion of gold in thin silicon slices has been investigated. Precision grinding together with γ‐scintillation counting was used to measure concentration profiles of 198Au diffused, over a temperature range 900°–1200°C, into thin slices of both high‐and low‐dislocation density silicon crystals. U‐shaped gold concentration profiles as observed by previous workers were obtained in all cases. Significant differences were observed between diffusion profiles in slices which had different initial dislocation content, but had undergone identical diffusion processing. This effect of dislocation density on gold diffusion is strong evidence to support the dissociative mechanism for gold diffusion in silicon. The differences between diffusion profiles in high‐ and low‐dislocation density material are interpreted by means of a model in which vacancy generation occurs at climbing grown‐in dislocations, but it is concluded that this may not be the only process determining the rate of gold uptake in thin slices.