Surface smoothing of CVD-diamond membrane for X-ray lithography by gas cluster ion beam

摘要

Results of the surface smoothing of a CVD-diamond membrane by gas cluster ion beams are presented. An as-deposited diamond mebrane with a surface roughness of 400 A Ra was irradiated by Ar cluster ions with a energy of 20keV. A very smotth surface of 30A Ra was obtained at a dose of 3X10~(17) ions/cm~2. This result can be clarified by computer simulation which shows that the surface smoothing of thediamond membrane was improved by a lateral sputtering of the cluster ions. However, a thin graphite layer was formed on the surface by contaimination of monomer ions in the cluster beam, which decreased the transparency of the diamond membrane. A subsequent irradiation with O_2 cluster ions removed these graphite layers.