In this study, SiF interaction with amorphous Si surface at normal incidence was investigated using molecular dynamics simulation at 300 and 600 K. The incident energies of 50, 100 and 200 eV were used. The results show that the deposition rate is not sensitive to the incident energy, while with increasing the surface temperature, the deposition rate decreases. The etch yield is sensitive to the incident energy and the surface temperature. The etch yield increases with increasing incident energy and temperature. After bombarding, a SixFy interfacial layer is formed. The interfacial layer thickness increases with increasing incident energy mainly through enhanced penetration of the silicon lattice. In the interfacial layer, for SiFx (x = 1-3) species, SiF is dominant and only little SiF3 is present. At the outmost and innermost of the interfacial layer, SiF species is dominant. Most of SiF3 species is concentrated above the initial surface. (C) 2007 Elsevier B.V. All rights reserved.