ENHANCING THE INTERPRETATION OF X-RAY PHOTOELECTRON-SPECTRA USING NUMERICAL-METHODS

X-ray photoelectron spectroscopy (XPS) has long been used as a surface analytical method for the determination of elemental composition and chemistry of a material. Small-ares analysis allows the comparison of different areas of a sample surface, while sputter depth profiling makes it possible to follow the specific chemistry as a function of depth. Often in XPS, peak overlap or subtle changes in chemistry may sometimes make the chemical-state analysis of the elements in a material difficult. By using a variety of numerical methods, it is possible to enhance the analysis and interpretation of surface analytical data. Such numerical methods would include linear least-squares fitting and target factor analysis. By using these methods it is possible to enhance the chemical-state interpretation and in many cases significantly increase the detection limits of specific elements. Several examples of the application of numerical methods are used to illustrate the enhancement of data interpretation of XPS data, with special emphasis on linescans and sputter depth profiles.