Planarizing technique for ion-beam polishing of diamond films

Diamond films, deposited on silicon substrates through microwave-assisted chemical vapor deposition, have been polished with a 500-eV beam of oxygen ions through the use of a planarizing layer. The films' surface roughness, in excess of 1 microm (rms) and 6 microm (peak to valley), was reduced to 35 nm (rms) and 217 nm (peak to valley). The polished films retained their diamond character and surface contamination was negligible. With this polishing process, optical applications of diamond films in the near infrared region are realizable.