Atmospheric Pressure PECVD of Fluorocarbon Coatings from Glow Dielectric Barrier Discharges

The deposition of fluorocarbon films from GDBDs fed with helium-hexafluoropropene (He-C(3)F(6)) and helium-octafluoropropane-hydrogen (He-C(3)F(8)-H(2)) mixtures was investigated. The effect of several parameters was evaluated in order to clarify both the GDBD existence domain and film characteristics. He-C(3)F(6) GDBDs allowed to obtain films with an F/C ratio of 1.5 and to achieve deposition rates up to 35 nm . min (-1). By changing the H(2) content in He-C(3)F(8)-H(2) fed GDBDs it was possible to vary the crosslinking degree, to tune the F/C ratio of the coatings and to change the deposition rate which was maximized for an H(2)/C(3)F(8) ratio close to 1. A spectroscopic investigation of the plasma phase is also presented.