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

Local density pseudopotential calculations find that the growth radical SiH3 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 SiH3 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. (C) 2002 Elsevier Science B.V. All rights reserved.