Raman spectroscopy is used to study C and Ge diffusion in multilayers of C-induced Ge dots deposited on Si(100). The initial Ge content is fixed to 2 ML and the C precoverage varied from 0.1 to 0.3 ML. The resulting concentration of isolated substitutional C atoms depends on the C precoverage and the thermal annealing performed after growth. C atoms are mostly localized in the areas around the dots, due to the repulsive Ge-C interaction. When C is added, the interface around the burried dots becomes sharper, and less Ge alloying occurs. C mainly increases the strain contrast around the dots and induces a strain-enhanced Ge interdiffusion, even at 650℃. At 800℃, Ge and C interdiffuse simultaneously.
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