Berlin 2005 – wissenschaftliches Programm
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P: Plasmaphysik
P 7: Poster: Niedertemperaturplasmen / Plasmatechnologie 3, Diagnostik 3
P 7.3: Poster
Freitag, 4. März 2005, 16:30–18:30, Poster HU
Study of the chemical composition in methane discharges by means of tunable diode laser absorption spectroscopy — •A. Serdioutchenko, I. Möller, and H. Soltwisch — Institut für Experimentalphysik V, Ruhr-Universität Bochum, 44780 Bochum, Germany
Low-temperature rf CH4 plasmas have been used for a long time for industrial purposes. Attempts to estimate the chemical composition of such plasmas by numerical calculations are hampered by the large number of different physical and chemical processes involved and various unknown parameters. In a previous work we reported on measurements of the source gas (CH4), one intermediate radical (CH3) and two dominant stable end products (C2H6 and C2H2) by means of tunable diode laser absorption spectroscopy1. It was found that the dependence of the species concentrations on the input power can be explained by relatively simple semi-empirical expressions. Recently we approved the assumptions made on the electron density with the help of a microwave interferometer. In addition, the analysis of C2H2 has been completed by investigating the missing production term originating from inelastic electron collisions with C2H4. Simple analytical approximations for the dominant plasma species allow us to define the main reaction channels and to estimate the corresponding rate coefficients. The obtained data can also serve for the verification of other more sophisticated plasma chemistry models.
1 A. Serdioutchenko, I. Möller and H. Soltwisch, Infrared diode laser absorption spectroscopy of C2H2 and C2H6 in capacitively coupled methane discharges, Spectrochimica Acta, Part A 60, 3311-3318 (2004)