Amorphous fluorinated carbon films have been prepared by plasma enhanced chemical vapor deposition method using C 6 F 6 at substrate temperature of 400 °C. Thermal stability up to 400 °C is automatically achieved. Dielectric constant of the films is 2. Infrared absorption spectra of the films have indicated that the films contain benzene rings, and F/C ratio is unity as seen in monomer molecules. No film deposition has been observed if C 5 F 8 is used as a source monomer at this substrate temperature. In situ Fourier transform infrared spectroscopy of C 6 F 6 plasma has indicated production of C 6 F 5 because C 12 F 10 has been observed. This result and inclusion of benzene rings in the films suggest that a possible deposition precursor is C 6 F 5 .