Data preprocessing in peak shape analysis of Auger electron spectra

Factor analysis is an established method of peak shape analysis in Auger el ectron spectrometry. The influence of different commonly used data preproce ssing tools onto the results of factor analysis is demonstrated on AES dept h profiles of multilayers and implantation profiles, For the analysis of Au ger electron spectra it has been traditional to differentiate spectra by Sa vitzky and Golay's method to remove background and to elucidate changes in peak shape. For phosphorus implanted in titanium it is shown that background removal wo rks not ideal so that inelastic losses of the Ti(LMM) Auger peak can affect the result of factor analysis for the P(LVV) peak located at ca, 250 eV lo wer in kinetic energy, The contribution of such losses to the background ca n be corrected by shifting the spectra so that the high energy side above t he peak equals zero, Numerical differentiation can introduce correlated err or into the data set. To diminish edge effects the reduction of filter widt h at the edges and cutting off the outermost data points is recommended. The precision of spectrum reproduction is considered as a crucial test for the number of principal components. The reliability factor is investigated as a measure for the goodness of spectrum reproduction.