Soft X-ray irradiation effect on the fluorinated DLC film

- The irradiation effect of the soft X-rays on fluorinated diamond-like carbon film was investigated.
- Various film properties and surface properties were found to be changed by the SR irradiation.
- Changes in film properties and film thickness did not proceed after the 300 mA h SR exposure.
- The stop of change in film properties was ascribable to the decrease of fluorine content in the F-DLC film.

The irradiation effect on fluorinated diamond-like carbon (F-DLC) film was investigated by measuring the dose dependence of various film properties using synchrotron radiation (SR) in the soft X-rays in the SR dose region from 0 to 2000 mA h. Film flatness was maintained but various film properties and surface properties were found to be changed by the SR irradiation. Wettability of the F-DLC film surface increased dramatically within 20 mA h SR exposure, which was ascribed to the decrease in fluorine on the film surface. Film thickness, film density, composition ratio of fluorine atom in film decreased and sp2 / (sp2 + sp3) ratio of carbon atoms increased within 300 mA h SR exposure, which were ascribed to the desorption of species containing fluorine atoms. In addition, dominant desorbed species emitted from F-DLC film were found in the fluorocarbon group, CFx. Changes in film properties and film thickness did not proceed, when fluorine content in the F-DLC film decreased to about 10% after the 300 mA h SR exposure.