Investigation on surface compositions of Cu-Ni alloy under Ar + ion bombardment by ISS and in situ AES measurements

Abstract

Surface compositions of Cu-Ni(50 wt%) alloy under 3 keV Ar + ion bombardment were measured by Auger electron spectroscopy (AES) and ion scattering spectroscopy (ISS). In situ AES measurement of sputter-deposited layer and sputtered sample surface indicated that surface composition became Ni-rich due to Ar + ion sputtering at steady state, in accord with previous reports of preferential sputtering. ISS measurements with 3 keV Ar + ions, however, have suggested that the composition of the outermost atom layer is not Ni-rich but slightly copper-rich. This leads to the conclusion that the degree of preferential sputtering is small and that the question of preferential sputtering, particularly, the ratio of the sputtering yields, S Cu/ S Ni, based on AES measurement requires further examination.