Sputtering of silicon carbide coatings by low-energy hydrogen ions

Various types of silicon carbide coatings made by reactive ion-plating have been bombarded with a 3.0 keV H⁺₃ ion beam at temperatures around 500°C. The sputtering yield in stoichiometric samples (i.e. Si : C = 1 : 1) at 500°C was 1.15 × 10^-2 atoms/H⁺. As the stoichiometry deviates from this point, the sputtering yield has larger values. The temperature dependence of the sputtering yield in stoichiometric samples was negligible below 600°C. No surface topography changes occurred in stoichiometric samples even at a high fluence of 2 × 10²⁰ H⁺/cm², while severe erosion took place in non-stoichiometric samples. By Auger electron spectroscopy (AES), carbon exists on the surface in the form of carbide in stoichiometric SiC before and after bombardment, while it exists in the form of graphite in carbon rich samples, which suggests that the bound state of carbon in the form of carbide should correspond to the low sputtering yield in stoichiometric SiC coatings. The surface stoichiometry changes due to hydrogen bombardment were observed by AES, where the carbon population increases in stoichiometric SiC, while it decreases in carbon rich samples, which was supported as well by the results from electron probe X-ray microanalysis.