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P: Plasmaphysik
P 4: Diagnostik 1; Niedertemperaturplasmen / Plasmatechnologie 2; Magnetischer Einschluß 2
P 4.26: Poster
Monday, March 27, 2006, 17:00–19:00, Flure
Radical densities in an inductively coupled CF4 discharge — •Victor Kadetov, Mariana Osiac, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, CPST, Ruhr-University Bochum, Germany
Fluorocarbon discharges are widely used in technical applications for plasma-assisted material processing. However, the detailed mechanisms for the production and destruction of different gas species in such discharges are not yet fully understood. In order to get insight into the elementary processes taking place in fluorocarbon plasmas, the dissociation degree of CF4 and absolute concentrations of CF, CF2, and CF3 radicals were measured using infrared laser absorption spectroscopy (IRLAS). A single-path scheme using a diode laser in the range of 1220-1280 cm−1 was used.
Measurements in the CF4 inductively coupled plasma (ICP) generated in a GEC reference cell were performed at 10 Pa for various powers. At low powers, the ICP operates in capacitive mode, or so-called, E-mode. The transition to inductive or H-mode occurs around 90-100 W. At powers of 100-400 W, instabilities in the plasma emission were observed. At powers above 400 W, the plasma operates is in stable H-mode. For all operating regimes, the absolute densities of fluorocarbon radicals were measured. This work is supported by MIWFT/NRW and GK 1051.