The relationship between structure, H coverage and reactivity of plasma-deposited hydrogenated amorphous Si film surfaces was investigated by using molecular dynamics simulations. The surfaces of hydrogenated amorphous Si films which were grown by using SiH3 as the sole deposition precursor, were found to be remarkably smooth. This was due to a valley-filling mechanism in which mobile precursors, such as SiH3 and Si2H6, diffused and reacted with dangling bonds in the surface valleys. The latter were reactive due to the increased concentration of dangling bonds and decreased H coverage in those regions. A previously suggested physisorbed configuration, in which SiH3 was weakly bound to the surface via a H atom, was concluded to be highly unlikely as a mobile precursor state.

Evolution of Structure, Morphology and Reactivity of Hydrogenated Amorphous Silicon Film Surfaces Grown by Molecular-Dynamics Simulation. S.Ramalingam, S.Sriraman, E.S.Aydil, D.Maroudas: Applied Physics Letters, 2001, 78[18], 2685-7