INVESTIGATION OF DAMAGE FORMATION BY GAS CLUSTER ION-BOMBARDMENT

Ar cluster ion bombardment has been carried out to study impact proces ses of cluster ions on solid surfaces with various ion energies. In th e case of Ar cluster ion bombardment with an energy of 150 keV, a dama ged layer of about 200 Angstrom thickness was formed. This thickness i s significantly larger than the value calculated for Ar monomer ions w ith the same velocity as the cluster ions. The thickness of the damage d layer is strongly dependent on the cluster size. Surprisingly, thick er damaged layers are formed with increasing cluster size, if the clus ter ion energies are same. These results strongly suggest a new damage formation mechanism by high-energy cluster ion bombardment.