Self-consistent calibration of TixC1-x auger spectra

Abstract

Auger sputter depth profiling was performed on a specially prepared TiC sample with carbon concentration varying with depth. This resulted in a series of Auger spectra corresponding to TixC1−x, with x varying between 0.1 and 0.95. Although the carbon concentration gradient is not known a priori, there exists a method to associate any of these spectra with a given stoichiometry, utilizing the smooth relationship between the C and Ti signal for a large range of stoichiometries and imposing the constraint of atomic fractions adding up to unity. In this way the stoichiometry of each spectrum has been determined, leading to a large series of standard spectra, that allow the stoichiometry of any unknown TixC1−x specimen to be calibrated on the basis of its Auger spectrum. 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 Auger peak-to-peak heights owing to chemical effects in the spectra. © 1998 John Wiley & Sons, Ltd.