Molecular beam epitaxial growth of Si on Ga-activated Si(111) surface

Molecular beam epitaxial (MBE) growth of silicon on gallium-activated Si(111) surface is investigated by microprobe reflection high-energy electron diffraction. Improvement in crystallinity is observed for a film grown on Ga adsorbed surface compared with that grown on a clean Si surface. Substrate temperature dependence of denuded zone width of two-dimensional (2D) nuclei is measured for various growth rates. The measurements give the activation energy of surface diffusion and the critical 2D nucleus size. Due to gallium adsorption on the surface, the activation energy becomes lower and the size becomes larger than those on the clean Si surface. This improves the crystallinity of the grown film. MBE growth of Si on partially activated surface is also reported. It is found that a film with good crystallinity grows selectively on Ga-adsorbed area.