Intermixing at the Ge/Si(001) surface was studied, for Ge coverages of 0.5 or 1 monolayer, by using pseudo-potential density-functional theory. The total energies of various Ge-Si intermixing configurations were calculated, and the possibility of Ge interdiffusion in the thermodynamic regime was estimated. It was found that, while most of the Ge atoms remained in the surface layer at room temperature, Ge interdiffusion tended to increase with temperature. These results provided a quantitative explanation for experimental observations of high-temperature Ge interdiffusion at the Ge/Si(001) surface, and also demonstrated that there was a strong Ge site-selectivity which arose from dimerized surface reconstruction.

Ge-Si Intermixing at the Ge/Si(001) Surface J.H.Cho, M.H.Kang: Physical Review B, 2000, 61[3], 1688-91