Thermodesorption of silicon from textured tantalum ribbons

The interaction of silicon with tantalum is studied by the Auger spectroscopy and temperature-controlled desorption technique. It is shown that, at a monolayer coating, the adsorbed silicon atoms penetrate into the bulk of a substrate at temperature T greater than or equal to 1400 K. The spectral shape and the annealing curves are explained by the influence of the Si-Si lateral repulsion in an adsorbed layer on the desorption and diffusion of the Si atoms into the bulk. Some ratios between the kinetic parameters are determined from analysis of the experimental data. Their application in numerical calculations based on the model proposed earlier makes it possible to determine (from comparison of the calculated and experimental data) the kinetic parameters for all the processes of the interaction between silicon and the tantalum substrate during the temperature-controlled desorption (desorption, transfer into the bulk, diffusion, and migration of silicon onto the surface). An adequate description of the experiment is obtained only under the assumption that the diffusion at the final stages of temperature-controlled desorption after reaching a maximum occurs within a thin layer near the surface, so that the migration of the Si atoms to the surface and desorption proceed more rapidly than their diffusion into the bulk. (C) 2000 MAIK "Nauka/Interperiodica".