Optimization of flux ratio of C 60 molecule to Ar cluster ion for diamond-like carbon film deposition by NEXAFS measurement

Abstract

To optimize the flux ratio of C 60 to Ar cluster ion during diamond-like carbon (DLC) film deposition, DLC films deposited under various flux ratios were characterized with Raman spectrometry and near edge X-ray absorption fine structure (NEXAFS). From Raman spectrometry, DLC films were deposited when the flux ratio of C 60 to Ar cluster ion was between 0.7 and 4. When the ratio was over 10, C 60 films were mainly deposited. As it was difficult to do precise characterization of DLC with Raman spectrometry, NEXAFS measurements were performed for the films deposited in the DLC deposition range of flux ratio. From NEXAFS spectra, there was no significant difference in sp 2 contents when the flux ratios were between 1 and 4. Hardness of these DLC films was between 40 and 45 GPa. Therefore very hard DLC film could be deposited with Ar cluster ion beam assist deposition over wide range of flux ratios, and this deposition process was very stable against changes of the flux ratio.