Polishing of CVD Diamond for Direct Bonding Using Ar and SF6-Gas Cluster Ion Beams

CVD diamond for direct bonding were polished using Ar and SF6-gas cluster ion beam (GCIB). The effects of gas variety on the removed thickness, surface roughness and the crystallinity of diamond surface were discussed. Results show that diamond was etched faster by SF 6 -GCIB than by Ar-GCIB with the same ion dose and acceleration voltage. For a smooth diamond surface, SF 6 -GCIB irradiation could decrease the surface roughness and smooth the surface further by increasing the ion dose. Most importantly, additional damages were not induced during this process. But it could not change the morphology of the diamond surface. While after Ar-GCIB irradiation, wave patterns on diamond surface disappeared with the sacrifice of a smooth surface, and the crystallinity of the diamond became poor.