The influence of substrate material and ion bombardment on fluorocarbon thin films deposited using a C2F6 glow discharge in an rf, parallel plate reactor was investigated. Monitoring of the plasma process by optical emission spectroscopy indicated that the dominant species in the glow discharge was CF2. Studies of bulk polytetrafluoroethylene (PTFE) and plasma-polymerized fluorocarbon thin-film samples in an XPS system demonstrated that the formation of non-CF2 species can be induced by ion bombardment of CF2 molecules. Characterization of the deposited fluorocarbon films by XPS found that the F/C ratio and CFx distribution (O < x < 3) in the films were dependent on processing conditions. Fluorocarbon films deposited simultaneously onto Al, glass, steel, and PTFE substrates using a C2F6 plasma and a graphite sputter target had measurably different F/C ratios, with the F/C ratio of the films deposited onto the Al substrates consistently lower than the F/C ratios of the films deposited onto the other substrates. When a C2F6 plasma was used without a graphite target, the F/C ratio in the film was constant, but the CFx distribution was different for each of the substrate materials. Analysis of the plasma-polymerized films by TEM revealed that localized growth of fluorocarbon particles occurred during the initial stages of deposition, consistent with an activated growth mechanism. Differences in the F/C ratio for films deposited onto the various substrate materials were attributed to the interaction of the fluorocarbon plasma with the exposed surface of the substrate prior to complete coverage by the polymeric film.