Depth profiling of polycrystalline multilayers using aBuckminsterfullerene projectile

Depth resolution of 5nm was achieved on a Ni:Cr multilayer structure using 15keV C60+ ion bombardment for depth profiling. The results, acquired by monitoring the sputtered neutral flux of Ni and Cr atoms, are of equivalent quality to those achieved using low-energy obliquely incident atomic beams with sample rotation. The reason behind these improved results is shown to be due to the unique ability of this cluster ion to remove material without regard to crystallographic orientation, hence reducing the buildup of topography.