Optimization of depth resolution parameters in AES sputter profiling of GaAs AlAs multilayer structures

Depth resolution, roughness and atomic mixing parameters in sputter depth p rofiling with AES were studied on GaAs/AlAs multilayers in dependence of th e type of sputtering gas (Ar, Xe, SF6), the ion energy and the ion incidenc e angle, using the mixing-roughness-information depth (MRI) model for profi le quantification and determination of the roughness and the mixing length. Both parameters were found to decrease with decreasing ion energy and incr easing incidence angle. For some samples, the surface roughness was additio nally measured by atomic force microscopy (AFM) after profiling. The lowest mixing length was obtained for 500 eV energy and 80 degrees incidence angl e and was 1.4, 0.8 and 0.4 nm for the ions of Ar, Xe and SF6, respectively. The very low mixing length for SF6 can be explained by the low impact ener gy of the atoms sharing the total energy of the ionized molecule. (C) 1999 Elsevier Science B.V. All rights reserved.