Erosion of Ag surface by continuous irradiation with slow, large Ar clusters

Molecular dynamics computer simulations are employed to probe processes taking place during continuous irradiation of Ag(1 1 1) surface by keV Ar872 projectiles. Surface modification, the total sputtering yield, and the angular distributions of ejected species are calculated at fluences ranging from 0 up to ∼6 × 1013 impacts/cm2. It has been shown that two trends can be identified in the development of surface roughness. At the beginning surface roughness increases fast. This fast increase terminates around 1 × 1013 impacts/cm2 and is followed by a slow increase that finally saturates. The effect of the surface roughness on the sputtering yield depends on the impact angle. At normal incidence the sputtering yield is rather insensitive to the development of the surface topography. Modification of the surface morphology has, however, a significant influence on the total sputtering yield at large impact angles. Both the shape of the sputtering yield dependence on the impact angle and the angular spectra of ejected particles are sensitive to the surface roughness.