HIGH-RESOLUTION COMPOSITIONAL DEPTH PROFILING

High (depth) resolution depth profiling by sputtering in combination with surface analysis techniques critically depends on an appropriate choice of experimental conditions. This requires a thorough understanding of the large number of parameters which generate characteristic deviations between the measured profile and the original shape of the in-depth distribution of composition. These parameters are mainly caused by instrumental factors, composition, crystallinity and morphology of the sample and the specific effects of ion beam-sample interactions. Recent results of Auger electron spectroscopy depth profiling of single- and multilayer structures with optimized experimental conditions, for example high ion beam incidence angle, sample rotation and crater edge profiling, show that a depth resolution in the low nanometer range can be obtained on smooth sample surfaces. The results are compared with predictive models for the dependence of the depth resolution on ion beam energy and incidence angle and on the sputtered depth, revealing the limiting parameters for various systems.