Adsorption and diffusion of a Si adatom on the H/Si(111) surface: comparison with the H/Si(001) surface

Using a first-principles method, we investigate the adsorption and diffusion of a Si adatom on the H-terminated Si(I 11) substrate, which would be useful in understanding the initial stages of Si homoepitaxy using a H surfactant. The adatom substitutes H atom(s) to form a monohydride structure or a dihydride structure. In forming the monohydride structure, the energy barrier for H substitution is absent. The adatom migrates on the surface with alternating its chemical state between monohydride and dihydride. These behaviors of the adatom are quit 6 similar to those on the H/Si(001)2 x 1 surface, despite the significant difference in the substrate structure between both orientations. The resulting diffusion barrier is 1.30 eV, which is also comparable to that on the H/Si(001)2 x 1 surface. (C) 2003 Elsevier Science B.V. All rights reserved.