VALIDITY OF THE METHOD FOR QUANTITATIVE XPS OF SURFACE NANOSTRUCTURES- APPLICATION TO CU AU/CU/

The validity of the software packet QUASES(TM), developed by Tougaard et al., for quantitative analysis by XPS of nano-scale surface structu res is considered. We study the ability of the software to consistentl y determine the same amount of Au atoms within the surface region of a series of solids where the depth distribution of a fixed number of Au atoms is varied. The sets of samples were produced by first evaporati ng a few monolayers of gold onto the surface of a polycrystalline copp er sample and then evaporating varying amounts of copper on top. A syn chrotron radiation source is used to produce the photons. For two seri es of samples where the measured Au 4d peak intensities vary by a fact or of 10, the quantitative amount of gold determined by this formalism is found to be constant to within an RMS deviation of 7% and 15%. Whe n the spectra from the same set of samples using photons of 950 and 75 0 eV energy are analyzed, the RMS deviation in the total number of gol d atoms is similar to 20%.