QUANTITATIVE REACTION DESORPTION APPLIED TO CARBON NEAR A MO(100) SURFACE

A reaction desorption study of a carburized Mo(100) surface combined with AES and a reliable method to quantify desorbed species is shown to give information about depth distributions of carbon near Mo surfaces. By these investigations the influence of heat treatments on the carbon distribution in subsurface layers is demonstrated. The subsurface region can absorb much more carbon than the bare surface, therefore acting as an additional reservoir for C atoms. Moreover the carburization of the subsurface layers causes a slowed C-diffusion due to carbide formation within this region. It turns out that the experimental results up to temperatures of 1183 K cannot be explained by the ''classical'' diffusion of C atoms into the bulk. These experimental results are supported by the results of simple computer calculations.