Surface Reactivity of CF₂ Radicals Measured Using Laser-Induced Fluorescence and C₂F₆ Plasma Molecular Beams

The surface reactivity of CF 2 radicals during plasma processing of a 300 K Si substrate using the imaging of radicals interacting with surfaces (IRIS) technique is reported. The molecular beam sources are 100% C 2 F 6 and 50:50 C 2 F 6 /H 2 plasmas. Under IRIS conditions, there is no net film deposition in the former system, while the latter deposits a fluorocarbon polymer film. Simulation of cross-sectional data shows a CF 2 surface reactivity of −0.44 ± 0.03 with 100%C 2 F 6 and of 0.16 ± 0.02 using 50:50 C 2 F 6 /H 2 . A negative reactivity indicates CF 2 molecules are generated through plasma processing of the substrate. Possible CF 2 surface generation mechanisms are discussed.