SELF-CONSISTENT CALIBRATION OF TIXC1-X AUGER-SPECTRA

Auger sputter depth profiling was performed on a specially prepared Ti C sample with carbon concentration varying with depth. This resulted i n a series of Auger spectra corresponding to TixC1-x, with x varying b etween 0.1 and 0.95. Although the carbon concentration gradient is not known a priori, there exists a method to associate any of these spect ra with a given stoichiometry, utilizing the smooth relationship betwe en the C and Ti signal for a large range of stoichiometries and imposi ng the constraint of atomic fractions adding up to unity. In this way the stoichiometry of each spectrum has been determined, leading to a l arge series of standard spectra, that allow the stoichiometry of any u nknown TixC1-x specimen to be calibrated on the basis of its Auger spe ctrum. Sensitivity factors and calibration curves established in this way are given for peak areas, while it was found that it is impossible to establish meaningful calibration curves for Anger peak-to-peak hei ghts owing to chemical effects in the spectra. (C) 1998 John Wiley & S ons, Ltd.