Surface layer evolution caused by the bombardment with ionized metal vapor

The evolution of the composition of tungsten carbide and silicon surfaces initiated by the bombardment with Zr and Cr ions has been investigated as a function of the substrate bias voltage. Surface composition profiles were measured by Rutherford backscattering and have been compared with the results obtained by the TRIDYN simulation program. It is found that the general dependence of film thickness on substrate bias is satisfactorily reproduced by this model. Deviations between experiment and simulation are attributed to possible partial oxidation of the surface or uncertainties in the charge state distribution of metal ions. The results confirm that TRIDYN facilitates the predictability of the nucleation of metallic vapor at substrate surfaces.