Small spot analysis with XPS

A comparison of the basic problems of image construction - when applied to elemental specific information - is given for electron probe microanalysis and XPS. Furthermore, the principles which allow an imaging XPS technique are reviewed and the advantages of the method developed by us are stated. First genuine experimental conditions of the existing instrument had to be provided, to assure a continuous control of the measurements and data handling. Measurements performed with this modified apparatus were used to determine the resolution and the time of data accumulation for specific experimental conditions. It is now possible for the first time to make visible the film thickness distribution of SiO2 on Si inhomogenously etched by Ar-ions over an area of 10 * 10 mm2, with a resolution of 0.2 * 0.2 mm2. To prove that a well-defined analysis is possible for single image points (pixels), the quantitative composition of four different Ag-Au-Cu specimens arranged side by side has been measured depending on time of data accumulation for a series of pixels. The analytical results were compared with the known bulk composition. (author, shortened)