The effect of biaxial strain on impurity diffusion in Si and SiGe

Abstract

Results from diffusion studies of different impurities in biaxially strained Si and Si 1 − x Ge x for low x-values will be presented. The structures are all molecular-beam epitaxy (MBE) grown on strain-relaxed Si 1 − x Ge x layers, and the impurity profiles are introduced during growth. We have in particular been concerned with the effect of biaxial strain (compressive and tensile) on the diffusion of pure vacancy-assisted diffusers (Sb and, partly, Ge) and pure interstitial-assisted diffusers (B and P). It is found that compressive biaxial strain retards the diffusion of the interstitial-assisted diffusers, whereas tensile biaxial strain enhances the diffusion of these impurities. The opposite is the case for the vacancy-assisted diffusers.