Evaluation of different models for the dissociation of silane on the Si(111)7×7 surface using the extended Brenner empirical potential

Several models have been proposed in the literature for the initial stages of the dissociative chemisorption of silane (SiH 4 ) on the Si(1 1 1)7 × 7 surface. In this paper, geometry optimisation calculations using the extended Brenner empirical potential have been performed to determine which of these models yields the minimum energy structure. The lowest energy configurations are found to correspond to the dissociation of silane into SiH 2 and two hydrogen atoms. The minimum energy structure involves the adsorption of the two hydrogen atoms onto the dangling bonds of an adjacent adatom and rest atom, and the insertion of the remaining SiH 2 fragment into one of the adatom backbonds. These results are discussed in the light of the existing experimental data.