Bochum 2002 – scientific programme

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P: Plasmaphysik

P 21: Poster: Grundprobleme, Theorie, Plasmatechnologie, Astrophysikalische Plasmen

P 21.26: Poster

Monday, March 18, 2002, 17:40–18:40, HZO Foyer

Spectroscopic Diagnostics of Dielectric Barrier Discharges (DBD) in Ar/CxFy mixtures — •I. Vinogradov, M. Shakhatre, and A. Lunk — Institut fuer Plasmaforschung, Universitaet Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart

The paper gives results of investigations of plasma polymerisation processes in a dielectric barrier discharge (DBD) at a pressure of one bar. FTIR- and UV- absorption as well as UV/VIS- emission spectroscopy were applied to get information on the absolute density of CF2: and the reaction products in a DBD running in Ar/fluorocarbon mixtures. XPS and REM were applied to get information of polymer layers (atomic contents and surface topology) deposited. The following fluorocarbon molecules have been studied: CF4, C2F6, C2H2F4, C3HF7, C3F8, and c-C4F8. From IR- absorption spectra of the DBD in mixtures of fluorocarbon with Ar almost all stable products were identified.

The dependence of CF2:- and CF3- absorption/emission intensities on polymer film deposition rate with F/C ratio as parameter was studied too. We found that polymer films can be deposited if the ratio F/C is smaller or close to 2. FTIR- absorption spectroscopy of films deposited on Si wafer indicates that the main absorption belongs to CF2-groups. In addition, absorption peaks which belong to “amorphous“ PTFE, CF3- groups as well as CF- groups were also observed in the spectra. Comparing the results of FTIR- absorption spectroscopy with those of XPS showed the influence of H2 concentration in the gas mixture on cross linking effects during plasma polymerisation processes.