Determination of the depth resolution of Auger electron spectroscopy depth profiles of anodic barrier oxide films on differently pretreated aluminium substrates

The virtual interface width in AES sputter depth profiles of amorphous anodic oxide coatings on aluminium is investigated. Even when the physical film–substrate interface is relatively sharp, considerable deterioration of the depth resolution may be caused by sputter‐induced roughness if sputtering conditions or the sample quality are not chosen properly. The effects of the oxide film thickness, choice of sputter angle and initial substrate roughness on the appearance of the interface width are investigated. A systematic study of the influence of Zalar rotation on the depth resolution is presented. It is concluded that long sputter times, due to film thickness or grazing sputter angles, and initial surface roughness cause a deterioration of the depth resolution. Zalar rotation generally improves the depth resolution for amorphous films, and is particularly indicated for the analysis of very rough samples. The sputter rate of amorphous films however, is insensitive to the use of Zalar rotation.