Aachen PK 2003 – wissenschaftliches Programm
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P: Plasmaphysik
P 17: Poster III
P 17.27: Poster
Donnerstag, 20. März 2003, 17:30–19:15, Foyer
Tunable diode laser spectroscopy measurement of the C2H6 and C2H2 production in a capacitively coupled rf discharge — •A. Serdioutchenko, I. Möller, and H. Soltwisch — Institut für Experimentalphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
In a previous work measurements of molecular densities of the source gases (CH4 and O2), an intermediate radical (CH3) and stable end products (CO and CO2) have been done. It was shown considering simple rate equations for CH4, O2 and CH3 that the species densities dependence on the applied power (roughly proportional to the electron density) can be explained by simple analytical expressions. The importance of processes, which lead to the C2H6 and C2H2 production was controversial.
Therefore in the present work the absolute densities of C2H6 and C2H2 have been investigated by means of tunable diode laser absorption spectroscopy in a capacitively coupled 13.56 MHz discharge under the following conditions (CH4 and O2 with different mixing ratio as source gases; total pressure 1 mbar, total flow rate 2 and 10 sccm, power 0-50 W).
The C2H6 and C2H2 densities have been found to be high enough in comparison with the CH3 density to consider their production as important reactions. A dependence of the C2H6 concentration on the flow rate is observed. Investigations of the C2H2 behavior with respect to the coupled power and flow rate changes are in process. Results from a simple chemistry model show similar trends in comparison with the measured densities, and absolute values are in the same order of magnitude. Further analysis of the influence of the C2H6 and C2H2 production on the CH3 density and the involved reaction paths is needed.