ENRICHMENT IN MOLYBDENUM CARBIDES AND NITRIDES DURING AR+ BOMBARDMENT

Alpha-Mo2C, delta-MoN and MoO3 interstitial compounds, obtained by direct metal gas interaction, were investigated by coupled Auger electron spectroscopy (AES) and ionic erosion with Ar+. It was found that, when the energy E(Ar+) varies from 3.5 to 1 keV, the relative AES signal h(x)(KL2,3L2,3)/h(Mo)(M4,5N2,3N4,5) (X = C and N in the case of the Mo-C and Mo N systems respectively) is attenuated. It indicates a preferential enrichment in molybdenum on the film surface at a low energy (less than 1.5 keV). The observed behaviour was interpreted in terms of preferential reimplantation and sputtering of C and N. The relative sensitivity coefficients of carbon, nitrogen and oxygen compared with molybdenum were also determined.