Berlin 2005 – scientific programme

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P: Plasmaphysik

P 14: Poster: Niedertemperaturplasmen / Plasmatechnologie 6, Diagnostik 4

P 14.3: Poster

Saturday, March 5, 2005, 14:45–16:45, Poster HU

Diagnostics of the afterglow of a Dielectric Barrier Discharge running in Ar/CxFy mixtures — •I. P. Vinogradov, M. Shakhatre, and A. Lunk — Institut fuer Plasmaforschung, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart

FTIR- and broad band UV- absorption spectroscopy diagnostics were applied in the afterglow of a dielectric barrier discharge (DBD-afterglow) running in Ar/fluorocarbon mixtures (C3HF7, c-C4F8) at a pressure of one bar in dependence on the gas flow rate and the power. The gas analysis was performed in the volume which is several mm (up to 10 mm) away from the active region of a dielectric barrier discharge. From all mentioned diagnostics tools only stable products in a DBD afterglow were identified. The analysis of data shows that there are no big differences between stable products in a DBD-afterglow in comparison to the active zone of a DBD. The concentration of CF2 depends linearly on gas flow rate. Only the absolute values of concentrations are different. In Ar/c-C4F8 the density of reaction products and also the film deposition rate are linear proportional to the gas flow rate and the discharge power. In C3HF7 no polymer film could be deposited in afterglow. AFM, REM and XPS methods were applied for analyses of polymer film deposited on silicon wafer. In DBD-afterglow the F/C ratio in the film is much higher (1.98) in comparison to F/C ratio of films produced in a DBD (1.44) at the same outer discharge parameters. From the results measured the question of the precursor species responsible for the film deposition in a DBD appears in a new light and will be discussed in detail.