Energetics and kinetics for Si-Ge intermixing on Ge-adsorbed hydrogenated si(100) surfaces

We present first-principles total-energy calculations for Ge adsorption on the H-terminated Si(100) 2 × 1 surface. The configuration with Si atoms at the topmost surface has the lowest energy among the various configurations for all Ge coverages considered, implying that Si segregation takes place in Ge growth on H/Si(100). Since Si segregation is a kinetic process, although driven by energetics, we consider an atomistic model for the place exchange between surface Ge and subsurface Si atoms based on the previous studies on the Si-adatom diffusion on H/Si(100). We argue that kinetics as well as energetics is important in understanding the Si-Ge intermixing near the interface.