Quantitative AES IX and quantitative XPS II: Auger and x-ray photoelectronintensities and sensitivity factors from spectral digital databases reanalysed using a REELS database

An extension has been made of previous analyses of peak area intensities fo r elemental spectra in digital Auger and x-ray photoelectron databases. The intensities, instead of being analysed after removal of a background deriv ed from the Tougaard Universal cross-section, are now analysed after remova l of the extrinsic characteristic loss background calculated by deconvolvin g the relevant angle-averaged reflected electron energy-loss spectroscopy ( REELS) spectrum. The angle-averaged REELS data for each element are calcula ted from a digital REELS database using a recently defined scaling of the m easured characteristic losses from the elastic peak. The new background rem oval procedure leads to an improvement in the correlation between experimen t and theory for intensities in both AES and XPS. Analysis of these correla tions shows that a systematic divergence remains for each element, which is the same for XPS as for AES. This divergence is attributed to an inadequac y either of the angle-averaged REELS method or of the material-to-material dependence of the TPP-2M equation used in the calculation of the inelastic mean free paths. Correction for this is possible in a new matrix-less quant ification formulation using average matrix sensitivity factors. This leads to correlations between experiment and theory with scatter factors of X/div ided by 1.08 and x/divided by 1.11 for AES and XPS, respectively, for a wid e range of elements and peaks. These scatter factors are much better than f or previous correlations and underpin the choice of formulae to calculate t he relevant theoretical intensity predictions. These calculations lead dire ctly to values of average matrix sensitivity factors, appropriate for use w ith spectrometers giving true spectra or with those spectrometers that may be calibrated to provide such spectra. (C) Crown Copyright 2001. Published by John Wiley & Sons, Ltd.