Diffusion coefficients and activation energies have been determined for Ge diffusion in strain-relaxed ${\mathrm{Si}}_{1-x}{\mathrm{Ge}}_x$ with $x=0.00\mathrm{}$, 0.10, 0.20, 0.30, 0.40, and 0.50. The activation energy drops from $4.7\mathrm{eV}$ in Si and ${\mathrm{Si}}_{0.90}{\mathrm{Ge}}_{0.10}$ to $3.2\mathrm{eV}$ at $x=0.50\mathrm{}$. This value compares with the literature value for Ge self-diffusion in Ge, suggesting Ge-like diffusion already at $x\approx 0.5$. The effect of strain on the diffusion was also studied showing a decrease in diffusion coefficient and an increase in activation energy upon going from compressive over relaxed to tensile strain.

• Received 8 May 2001

DOI:https://doi.org/10.1103/PhysRevLett.87.125901