Quantification of Au deposited on Ni: XPS peak shape analysis compared to RBS

We investigated the degree of quantitative agreement between XPS peak shape analysis and RBS with respect to the average thickness of Au layers deposited on Ni. Gold layers in the range of 5–100 Å were prepared on five substrate samples. By peak shape analysis of the Au 4d XPS peaks, the structure and amount of Au was determined. Likewise, by measuring with RBS on 3–5 regions of each sample the Au thickness in these regions was determined. Comparing the results, we determined the deviation between XPS and the mean value of the RBS thickness. For three of the samples the deviations were 6–7%. For the remaining two samples the agreement was worse. However, as shown by the scatter in the RBS results for each sample, the disagreement was due to a non‐uniform Au layer and not to the techniques. It is found that the absolute accuracy of the XPS peak shape analysis technique is ∽7% for depths of ⩽7–8 IMFP. © 1999 John Wiley & Sons, Ltd.