Diffusion in strained Si(Ge)

Experiments on Si-rich SiGe layers show an exponential increase in Ge diffusion and an exponential decrease in B diffusion as a function of compressive strain, indicating a linear dependence of activation energy on strain. The effect arises from the structural relaxation of the lattice around the defect mediating diffusion (inward for a vacancy, outward for an interstitial). We infer the mechanisms of Ge and B diffusion in strain-free and compressively strained Si(Ge) at T1030 \ifmmode^\circ\else\textdegree\fi{}C, and draw some general conclusions on strain-modified diffusion in crystalline solids.