Optimization of rotational Auger depth profiling

Abstract

AbstractThe dependence of depth resolution on the rate of sample rotation in rotational Auger depth profiling was systematically investigated for Cu/Fe multilayer films, using 1–3 keV Ar+ and Xe+ ions as projectiles. Except for Xe+ ion bombardment at 1 keV, the depth resolution was invariably improved by increasing the rate of rotation up to a critical value. The resolution improvement was more pronounced for Ar+ sputtering, but at and above the critical rate the resolution was nearly constant, independent of the sputtering conditions. The critical rotation rate depended on ion species and energy, decreasing with lowering ion energy and increasing ion mass. For 1 keV Xe+ the depth resolution obtained without rotation was comparable to that obtained with sample rotation, indicating that sample rotation was not the sole means to attain high depth resolution. As confirmed by scanning electron microscopy, highly resolved depth profiles for rotated samples were due mainly to reduced surface roughening. Evidence is also presented that at the critical rate of rotation the depth resolution was limited by the intrinsic interface roughness.