Alloy Sputtering Studies with <i>in situ</i> Auger Electron Spectroscopy

Abstract

Triode sputtering and Auger electron spectroscopy were combined in an uhv apparatus for in situ studies of the composition of ion-bombarded surfaces of alloy targets and of sputter-deposited films. The changes in surface composition of a 55 Cu–45 Ni alloy (Constantan) target were studied under Ar+-ion bombardment as a function of bombarding energy. Below 150 eV ion energy, the Cu/Ni sputtering ratio increases steeply with decreasing ion energy. This causes the nickel to become much enriched in the target surface. By ion bombarding a substrate during film deposition (biasing) one can produce a film which has an altered composition throughout. By varying in our geometry the bias voltage we were able to change the film composition from that of the target to one in which the Cu concentration was only 5% that of the Ni. The depleted species in this case appears as enrichment in films at other less biased surfaces (such as at the anode in triode systems).