Augsburg 2006 – wissenschaftliches Programm

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P: Plasmaphysik

P 15: Diagnostik 2; Niedertemperaturplasmen / Plasmatechnologie 5; Plasma-Wand Wechselwirkung 1

P 15.29: Poster

Dienstag, 28. März 2006, 17:00–19:00, Flure

Time-resolved measurements of transient and stable species in argon/methane pulsed ICP discharges — •V. Vartolomei, T. Schwarz-Selinger, and W. Jacob — Max-Planck Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching, Germany

The aim of this study is to identify elementary reaction mechanisms in methane plasmas. A description of this system is, however, very complicated due to the complexity of the reactions in the plasma volume and at the surface, and the interplay between both. Inductively coupled plasma (ICP) discharges in argon, methane, and methane/argon mixtures are investigated for continuous and pulsed operation. Neutral species are sampled with molecular-beam mass spectrometry at the chamber wall and ion fluxes are measured with energy-resolved mass spectrometry and a retarding field energy analyser at the substrate position. We focus here on the plasma volume reactions. To reduce the system complexity for the methane discharge, chemical reactions must be limited. This is performed by adding argon and by reducing the average dissipated energy per molecule in the discharge (Emean). This is achieved by varying experimental parameters such as power, residence time, and pulse parameters. As a first step, basic characteristics of the discharge and the analysis methods are characterised by pure argon discharges. As a second step increasing amounts of methane are added to the discharge. We observed that the pulse-averaged species concentration is determined by Emean only. Time-resolved measurements show that some species are produced in the pulse-on phase while others are depleted and vice-versa.