Surface Characterization and Lubricant Performance on Amorphous Carbon Films Irradiated With Gas Cluster Ion Beams

Irradiations of gas cluster ion beams (GCIB) on amorphous carbon films formed with chemical vapor deposition (CVD) were performed, and the affinity with lubricant was studied. The surface roughness of as-deposited amorphous CVD carbon film was improved with N₂ -GCIB irradiation. By reducing the formation of multiply charged cluster ions, large crater formations can be minimized, which helps to obtain smooth surface. It was also shown that nitrogen rich surface was formed on the amorphous CVD carbon with N₂ -GCIB. From the study of lubricant affinity and the surface free energy measurements, nitrogen containing functional groups were formed with N₂-GCIB irradiation, as a result, adhesion between the lubricant and the amorphous CVD carbon film increased.