SURFACE-ROUGHNESS EFFECTS IN QUANTITATIVE XPS - MAGIC-ANGLE FOR DETERMINING OVERLAYER THICKNESS

The use of X-ray photoelectron spectroscopy (XPS) as a technique for n on-destructive depth profiling of technical samples is often hindered by their roughness. In this paper, we elaborate on earlier work where we reported on the apparent existence of a 'magic' angle for the deter mination of the thickness of uniform overlayers on rough substrates, S imple calculations for fully three-dimensional model rough surfaces st rongly suggest that the thickness of an overlayer on a rough substrate can be determined accurately without taking the roughness into accoun t in the analysis of the XPS intensities, the neglect of roughness eff ects leading to an average error less than 10% in the determined thick ness. (C) 1997 Elsevier Science B.V.