A variety of analytical tools have been used to examine the gas-phase and surface chemistry of SiF4 and SiF4/H-2 plasmas interacting with Si substrates. The effect, of rf power (P) and source gas ratios on film composition, gas-phase species densities, and plasma-surface interactions of SiF and SiF2 have been studied. Film characterization was performed using Fourier transfer infrared, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry. Using the imaging of radicals interacting with surfaces technique, spatially resolved laser-induced fluorescence images of. SiF,, radicals were collected and used to characterize both the plasma-surface interface and the gas phase. Additional gas-phase characterization was achieved using optical emission spectroscopy and mass spectrometry. From all of these data, three plasma types have been defined. In etching systems'(type 1) (e.g., 100% SiF4 plasmas at P > 20 W), no net deposition occurs, and SiF2 radicals are produced at the surface. When only F atom incorporation occurs with no net etching or deposition (type 2), SiF2 can exhibit either surface loss or surface production, depending on other plasma parameters. In a-Si:H,F film depositing systems (type 3), SiF2 is lost at the surface under most conditions. Gas phase and surface mechanisms to describe these three plasma types are proposed. (C) 2003 American Vacuum Society.