Investigation of the low-pressure plasma-chemical conversion of fluorocarbon waste gases

Decomposition of SF6in an RF Plasma Environment

“…13 The mole fraction of SiF 4 increased from 0.18 to 0.23% when the input power was varied from 5 to 20 W (Figure 3). Thus, more F radicals were produced, and the etchable wall surface also increased with the plasma contact area under higher input power (Figure 4), which was consistent with the assumption of Breitbarth et al 12 that the SiO 2 etch rate was proportional to the plasma power. However, as the power exceeded 40 W, η SF6 remained constant and resulted in the stable production of SiF 4 .…”

“…4,[6][7][8][9][10] Particularly toxic is S 2 F 10 , which has an LC 50 (concentration needed to kill 50% of a defined experimental animal population) of 0.1 mg/m 3 . 11 Because reducing or eliminating the toxicity of gaseous effluent from the RF discharge process is a serious concern, Breitbarth et al 12 have proposed an oxygen-based RF discharge process in which a glass reactor is connected in series with a commercial RF parallel-plate reactor to decompose fluorocarbon waste gases into CF 4 and C 2 F 6 , which, in the presence of silica walls, are reacted to stable SiF 4 . The SiF 4 then can be converted into nontoxic solid products with the aid of a CaO/Ca(OH) 2 absorber.…”

Tailoring the Properties of Asymmetric Cellulose Acetate Membranes by Gas Plasma Etching

“…From the literature it is known that fluorine radicals present in a CF 4 plasma can react with Si x O y yielding volatile Si x F y fragments and atomic oxygen (29). Although this could induce some silica ablation at the surface during CF 4 plasma etching, it does not fully explain the complete lack of silicium at the surface of continuously treated CTA membranes.…”

Comparative Study on the Decomposition of Chloroform in Thermal and Cold Plasma

“…Some plasmaassisted decompositions of halogenated hydrocarbons have been reported in the recent literature. (6)(7)(8)(9)(10)(11) However, both data of thermodynamic calculations and the complete comparative study of these compounds have great theoretical and practical importance. Both high-energy thermal plasmas and electron beam irradiation or electrical discharge processing methods have been considered as highly efficient media for use to decompose gaseous reactants.…”