Relative sputter rate measured in Cu/Co multilayer using Ar+ ion bombardment at grazing angle of incidence

Abstract

The relative sputter rate of copper with respect to cobalt was determined by means of Auger electron spectroscopy depth profiling a Co/Cu multilayer structure as a function of the angle of incidence in the range of 47°–86° at 1 keV Ar+ ion bombardment. It was found that the relative Cu/Co sputter rate, YCu/YCo, decreases from 47° to 82°, exhibiting a minimum at 82°. Above 82° it sharply increases. In the literature we did not find sputtering yield data for such sputtering conditions. TRIM simulation and the Yamamura et al. (Y. Yamamura, Y. Itayekawa, and N. Itoh, Nagoya University of Plasma Physics Report JPPJ-AM-26) equation were compared with the experimental data. Though both predict the increase of YCu/YCo at high angles of incidence, the agreement between the theories and experiment is poor. Reasonably good agreement between the measurements and TRIM simulation was found if the surface binding energy of Cu was chosen to be an unphysical low value.