Widely changing probability of surface damage creation induced by a single ion in the MeV ion energy range

We report widely changing probability of surface damage creation induced by a single ion on highly oriented pyrolytic graphite specimens, each implanted with 3.1 MeV Si, Cu, As, Sr, Ag, or Au ions at a dose of 1.9x10(11) cm(-2). By using a friction force microscope, we observed lattice disordered surface damage, and found the probability of surface damage creation varying from 0.02 to 0.54 depending on the variation in the ion species. To determine the reason for the larger dependence on ion species, we calculated the probabilities of knock-on atom generation by nuclear collision. The calculated probability of knock-on atom generation agreed well with the observed probability of surface damage creation. (C) 1998 American Vacuum Society.