Depth resolution in Auger depth profile analysis of aluminum metallization in microelectronics: The effect of crystalline texture

Abstract

Due to the wide application as metallic interconnect material, aluminum alloys are important for integrated circuit technology. Analysis of aluminum thin films by Auger depth profiling, however, is impeded by severe roughening of the aluminum surface during the ion bombardment. It is shown that this is caused by the effect of ion channeling on the sputtering yield, resulting in an orientation-dependent sputter rate of the individual crystallites. Because of the strong crystalline texture of aluminium films, roughening is enhanced if the ion incidence coincides with the preferred orientations of the channeling axes. The dependence of depth resolution on ion impact angle, ion species and ion energy can be explained qualitatively by Onderdelinden's theory of single-crystalline sputtering. © 1990.