Atmospheric pressure PE-CVD of fluorocarbon thin films by means of glow dielectric barrier discharges

Glow dielectric barrier discharges (GDBDs) fed with He-C3F6 and He-C3F8-H-2 gas mixtures were used to deposit fluorocarbon thin films. The deposition process was studied inside the GDBD existence domain as evaluated by electrical measurements. The composition and structure of the deposited coatings were investigated through Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, Water Contact Angle measurements, and Scanning Electron Microscopy. He-C3F6 gas mixtures generate fluorocarbon films with F/C ratio of 1.5 at deposition rates up to 34 nm center dot min(-1), while with He-C3F8-H2 fed GDBDs it is possible to tune the F/C ratio of the coating from 1.5 to 0.6 and to change its cross-linking degree by varying the hydrogen concentration in the gas feed. H-2 addition promotes the increase of the deposition rate which is maximum for fluorocarbon-to-hydrogen ratio close to 1. Results of optical emission spectroscopy investigation of the plasma phase are also presented