A quantitative auger electron spectroscopy method (applied to a thin film monolayer overgrowth)

Abstract When a thin film grows in a monolayer overgrowth fashion, the AES signal versus film thickness is calculated by a quantitative AES method. The method is applied to the Cases of Ag on Au, Mo on W and Be on Cu. The calculated results agree very well with the experimnetal results. In this method, the following points are considered: (1) the attenuation of a primary beam, (2) the effects of back-scattered and forward-scattered electrons both from thin film and substrate materials, (3) the escape depths of any electrons, and (4) the effect of the three-dimensional movements of secondary electrons and Auger electrons in the solid. Consequently, especially from the above effect (4), the curve of Auger electron signal intensity versus film thickness can be estimated for the various optics (e.g. Cylindrical Mirror Analyzer (CMA), Low Energy Electron Diffraction (LEED) optics,…) used for the usual Auger experiments. Electron mean free paths can be obtained by the interpolation or the extrapolation for the different atomic numbers and the different energies from the published experimental result of Mo and W. The result by this method has a similar tendency as the result obtained by Penn. Also, the number of back-scattered and forward-scattered electrons can be estimated by the coefficient of secondary electrons with energy above the ionization electron energy E C to produce Auger electrons. Then, the values of the secondary electron coefficients are measured and tabulated for the 20 different elements from Be to U as a function of the ionization electron energy.