Optical Emission Spectroscopy of Argon–Fluorocarbon–Oxygen Fed Atmospheric Pressure Dielectric Barrier Discharges

Atmospheric pressure filamentary dielectric barrier discharges (FDBDs) fed with argon, a fluorocarbon compound (i.e. CF 4 , C 3 F 8 , C 3 F 6 and c‐C 4 F 8 ) and O 2 were investigated by optical emission spectroscopy (OES). The UV–Vis spectra of the plasma in argon–fluorocarbon mixtures are characterized by narrow signals from Ar atoms, CF 2 and CF fragments and by two continua due to CF   2 +and CF 3 . O 2 addition to the feed gas reduces the emissions of fluorocarbon fragments and results in the appearance of an intense narrow emission at 193 nm and of a broad continuum centred at 290 nm ascribed to ArF and Ar 2 F excimers, respectively. Any signal from F atoms was not detected under the experimental conditions investigated even though the plasma contains F atoms since the dry etching of silicon substrates, a typical process driven by F atoms, was observed. Some possible explanations of this phenomenon are presented.