Using a first-principles calculation method, an investigation was made of the adsorption and diffusion of a Ag adatom on the H-terminated and clean Si(111) surface, which would be useful in understanding the initial stages of metal growth on semiconductor substrates. Extensive studies were made of the metastable surface structures induced by Ag adatom adsorption, and the diffusion barriers and pathways on both kinds of substrate were then found. The calculated barrier for the Ag atom on the H-terminated surface was only 0.14eV. On the clean surface, the diffusion barriers inside a half–unit cell and between half–unit cells were calculated at 0.27 and 0.88eV, respectively. The present results provided a qualitative description of the Ag growth modes on the Si(111) surfaces: the 3-dimensional island growth on the H-terminated surface and the formation of the wetting layer on the clean surface. In addition, the calculated barrier of 0.88eV agreed well with the diffusion barrier measured by recent scanning-tunneling microscopy.

Diffusion of Ag Adatom on the H-Terminated and Clean Si(111) Surfaces - a First-Principles Study. H.Jeong, S.Jeong: Physical Review B, 2005, 71[3], 035310 (7pp)