Theoretical study of epitaxial growths on As-covered Si(100)surfaces

摘要

We investigate the energetics, diffusion, and reaction paths of Siand Ge adatoms on As-covered Si(100) surfaces through first-principlespseudopotential calculations. We find that at a monolayer coverage,individual Ge or Si adatoms incorporate rapidly into subsurface As siteswith minimum surface diffusion. Thus, the segregation of As to thesurface is initiated by single adatom exchange. Due to rapid adatomexchanges, the adatom mobility on surface is drastically reduced,compared to the growth mode without surfactants, resulting in a highdensity of two-dimensional islands. Generalized gradient corrections tothe LDA energies do not alter our results