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

Abstract

Atmospheric pressure filamentary dielectric barrier discharges (FDBDs) fed with argon, a fluorocarbon compound (i.e. CF4, C3F8, C3F6 and c‐C4F8) and O2 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, CF2 and CF fragments and by two continua due to CF 2+ and CF3. O2 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 Ar2F 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.

Energetics of reactions in a dielectric barrier discharge with argon carrier gas: VIII hydrofluoromethanes

“…The shapes of the E m curves for each different molecule as a function of F d will be discussed and correlated with optical emission spectroscopy (OES) as a diagnostic of the plasma physicochemistry, along with deposition rates, water contact angles (WCA), and chemical compositions of the resulting PP coatings, the latter determined by X‐ray photoelectron spectroscopy (XPS). From a practical point of view, fluorocarbon precursors have always been important in plasma chemistry because they can give rise to “poly(tetrafluorothylene), PTFE‐like” surfaces and coatings, also in AP DBD reactors . To the extent possible, the present results are compared with those earlier publications.…”

“…The reader is referred to articles by Fanelli and by Vinogradov and Lunk, authors who dealt in considerable detail with OES of DBD plasmas in Ar/CF x gas mixtures. According to Fanelli, the very broad “CF 2 ” band (ca.…”

Effect of Gas Impurities on the Operation of Dielectric Barrier Discharges Fed with He, Ar, and Ar‐C3F6

“…The UV–Vis emission spectra of the DBD were characterized by intense Ar emissions,49, 52, 53 by the emission bands of CF 2 (A 1 B 1 –X 1 A 1 system)49, 53, 54 and CF (B 2 Δ–X 2 Π system)49, 53, 54 and by two continua centered at approximately 290 and 620 nm, ascribed to ${\rm CF}_{{\rm 2}}^{{\rm + }} $ 49, 53, 55 and CF 3 ,49, 53, 55 respectively.…”

Thin film deposition and surface modification with atmospheric pressure dielectric barrier discharges

“…5. The spectra are dominated by an intense narrow emission at 193 nm and a broad continuum centred at 290 nm ascribed to ArF and Ar 2 F excimers, respectively [47]. Without oxygen, several emission features of CF and CF 2 are overimposed to the continuum emission centred at 290 nm, which also includes the broad emission of CF 2 + .…”