Sputtering-induced surface roughness is the main source of degradation of the depth resolution observed during depth profiling of polycrystalline metals. Atomic force microscopy (AFM) images of polycrystalline Al films at different mean sputtered depths are used to calculate both the depth distribution function (DDF) and the angular distribution function (ADF) of the evolving Al grain surfaces. The shape of the DDF changes with increasing mean sputtered depth, which implies the generation of two different roughness stages during sputtering. However, Auger electron spectroscopy (AES) depth profiling and AFM results show a linear increase of roughness vs. mean sputtered depth in the case of evaporated, polycrystalline Al films. A simple model is developed to calculate the AES intensity for a rough surface. The intensity behaviour as a function of the sputtering time depends on the ADF of microplanes and on the sample tilt angle and generally shows a marked decrease for high tilt angles. The sputtering rate distribution is determined using the DDF. A good fit of the AES depth profile of the Al film requires both the calculated intensity behaviour and the convolution using the DDF, which depends on the sputtering time. © 1998 John Wiley & Sons, Ltd.