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 induc ed by a single ion on highly oriented pyrolytic graphite specimens, ea ch 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 l attice 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 gener ation by nuclear collision. The calculated probability of knock-on ato m generation agreed well with the observed probability of surface dama ge creation. (C) 1998 American Vacuum Society.