Model for large cluster emission in ion sputtering of metals applied to atomic and polyatomic ion bombardments

We propose a model for the emission of large clusters (N greater than or eq ual to 5) under ion bombardment of metals. In the frame of this model, the relative cluster yields have been calculated as a function of the number of atoms in the cluster for the sputtering of Al, Ag, Ta and Nb targets by at omic and polyatomic ions with energies of several keV/atom. The calculated data have shown a very good agreement with experimental results obtained by us and other researchers. On the basis of this agreement we have concluded that larger clusters are emitted as whole agglomerates during the early st ages of the collision cascade evolution. (C) 1999 Elsevier Science B.V. All rights reserved.