Primary Ar+ ion bombardment effect on Ni–Fe film composition formed by ion beam sputtering

Abstract

This paper reports results of experimental and analytic investigations concerning the Ni–Fe film composition formed by ion beam sputtering under various forming conditions. From experiments involving the substrate angle and temperature that had dramatic influence on the Ni–Fe film composition, it is found that the primary Ar+ ion bombardment dominates the composition variation. Also, the Ni fraction in Ni–Fe film and its deposition rate decrease as the ion current density increases. As a result of simple analysis, this composition variation is found to be caused by preferential resputtering. Conversely, the Ni fraction increases as the substrate temperature increases without a deposition rate change under primary ion bombardment. This phenomenon cannot be explained only by preferential resputtering. It also includes the formation of an Fe-rich layer on the film surface.