The gas-phase density and surface interactions of the carbon trimer C-3 have been examined in fluorocarbon and hydrocarbon plasmas. The (1)Pi(u)-(1)Sigma(+)(g) fluorescence excitation spectra and relative 9 gas-phase densities of C-3 radicals have been collected using laser-induced fluorescence (LIF) spectroscopy. The relative C-3 density increases significantly with CH2F2 in the feed, indicating that C-3 is primarily produced via decomposing CH2F2 and chemical reactions in the gas phase. In addition, the surface reactivity R of C-3 has been measured during fluorocarbon and hydrocarbon film depositions using C3F8/CH2F2 and CH4/CH2F2 13.56 MHz rf plasmas. The C-3 radicals were characterized using our LIF-based imaging of radicals interacting with surfaces technique. R values for C-3 range from 0.10 to 0.38, depending on plasma conditions, but show no clear dependence on the gas mixture or the plasma conditions used. X-ray photoelectron spectroscopy measurements of the films deposited in these systems provide additional evidence that suggests that C-3 carbon clusters may be contributing to the formation of more cross-linked films. (c) 2007 American Vacuum Society.