Diffusion coefficients and activation energies were determined for Ge diffusion in strain-relaxed Si1-xGex, where x was 0, 0.1, 0.2, 0.3, 0.4 or 0.5. The activation energy decreased from 4.7eV for Si and Si0.90Ge0.10, to 3.2eV at an x-value of 0.5. This value was comparable with published data for Ge self-diffusion in Ge; thus suggesting that Ge-like diffusion occurred already at x-values of about 0.5. The effect of strain upon diffusion was also studied, and revealed a decrease in diffusion coefficient and an increase in activation energy upon going from compressive to tensile (table 44, figure 4).

Ge Self-Diffusion in Epitaxial Si1–xGex Layers. N.R.Zangenberg, J.Lundsgaard Hansen, J.Fage-Pedersen, A.Nylandsted Larsen: Physical Review Letters, 2001, 87[12], 125901 (4pp)

Table 44

Diffusivity of Ge in SiGe