Theoretical calculations of the AES intensity–film thickness functions for different growth models

Abstract

The surface spectroscopic methods, e.g. AES and XPS, are widely used in studies of thin film growth. In experiments spectroscopic data are recorded as intensity–film thickness curves. Much theoretical effort had been devoted to calculation AES intensity–thickness functions for different growth modes. A key element of such calculations is finding coverage in each layer. Recently, we developed two models of thin film growth that allow exact determining of coverage in all layers of a growing film. In island growth model the lateral islands growth occurs via capture of migrating adatoms whereas their vertical growth-owing to direct impingement of deposited atoms. Analysis of arising film morphology yields coverage in each layer in analytic form. In layer growth model based on rate equation approach combined with a feeding zone accounting for interlayer mass transport coverage in successive layers are calculated in a straightforward manner. Thus the AES intensity–film thickness functions were derived analytically for island growth and computed numerically for layer growth in various growth regimes (complete/incomplete condensation) and modes (smooth/rough), enabling experimental data to be examined quantitatively and in greater detail than has previously been reported.