DETERMINATION OF THE DEPTH RESOLUTION OF AUGER-ELECTRON SPECTROSCOPY DEPTH PROFILES OF ANODIC BARRIER OXIDE-FILMS ON DIFFERENTLY PRETREATEDALUMINUM SUBSTRATES

The virtual interface width in AES sputter depth profiles of amorphous anodic oxide coatings on aluminium is investigated. Even when the phy sical film-substrate interface is relatively sharp, considerable deter ioration of the depth resolution may be caused by sputter-induced roug hness if sputtering conditions or the sample quality are not chosen pr operly. The effects of the oxide film thickness, choice of sputter ang le and initial substrate roughness on the appearance of the interface width are investigated. A systematic study of the influence of Zalar r otation on the depth resolution is presented. It is concluded that lon g sputter times, due to film thickness or grazing sputter angles, and initial surface roughness cause a deterioration of the depth resolutio n. Zalar rotation generally improves the depth resolution for amorphou s films, and is particularly indicated for the analysis of very rough samples. The sputter rate of amorphous films however, is insensitive t o the use of Zalar rotation.