Binding and surface diffusion of SiH3 radicals on a growing a-Si:H surface

Abstract Local density pseudopotential calculations find that the growth radical SiH 3 binds to the hydrogen terminated (1 1 1)Si surface. The bound site is not the three-centre Si–H–Si bridging site assumed previously. Instead, it has a direct Si–Si bond between the SiH 3 and the surface Si, and the terminal hydrogen has been displaced first to an antibonding site and finally to a bond centre site of a surface Si–Si bond. A bound site validates conventional models of the growth of hydrogen amorphous silicon (a-Si:H), in which a mobile growth species is needed for smooth surfaces.