PLASMA-ENHANCED DEPOSITION OF DIAMOND-LIKE CARBON-FILMS ON HIGH-TEMPERATURE TOLERANT POLYMERS

The feasibility of depositing carbon films with a diamond-like structu re on high temperature polymers, using established plasma-enhanced che mical vapor deposition techniques, is explored. Potential uses for suc h a film will depend upon the adhesion of the film to the substrate, t he properties of the deposited film, and the effect of the deposition process on the bulk properties of the polymer substrate. Amorphous car bon (diamond-like carbon) coatings with thicknesses ranging from 2 to 18 mum were deposited on polyimide substrates at temperatures below 42 0-degrees-C. Extended exposure to the plasma processing conditions cau sed no visible damage but halved the room-temperature tensile strength of the polymer films. Diamond-like carbon, graphitic carbon, and a pr ecursor to the diamond-like carbon structure, attributed to an aromati c carbon ring structure, were observed. The optical transparency of th e coated polymer film was attenuated uniformly across the spectral ran ge, 2.5-22 mum. Static oxidation and limited thermal cycling of the co ated polymer produced no widespread delamination of the coating from t he substrate: neither the deposited film nor the coated regions of the polymer showed any effect when oxidized at 370-degrees-C, for 450 h. (C) 1994 John Wiley & Sons, Inc.