Hannover 2010 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 8: Poster: Low Temperature Plasmas I
P 8.3: Poster
Dienstag, 9. März 2010, 16:00–18:00, Lichthof
Analysis of fast neutral oxygen atoms in capacitively coupled rf plasma — •Kristian Dittmann1, Bert Krames1, Timo Gans2, and Jürgen Meichsner1 — 1University of Greifswald, Institute of Physics, Greifswald, Germany — 2Queen's University Belfast, Centre for Plasma Physics, Belfast, Northern Ireland
Measured axially and temporally (RF phase) resolved plasma induced optical emission of the atomic oxygen, e.g. at 777.4 nm, together with PIC-MCC simulation have been shown characteristic excitation patterns in front of the powered electrode. The different pattern have their origin in electron impact excitation due to electron heating during the sheath expansion phase, energetic electrons in the sheath collapse phase due to electric field reversal, secondary electrons including electrons from detached negative ions, and the electronic excitation due to heavy particle collisions. Furthermore, the analysis of positive ions at the powered electrode by means of energy resolved mass spectrometry and PIC-MCC simulation provide information on the energetic ion current. The observed excitation of atomic oxygen by heavy species collision is coupled with the energetic ion flux. First measurements of the emission line profile of the excited atomic oxygen due to heavy particle collision show Doppler-shifted fractions of fast neutral oxygen atoms. These fast oxygen atoms, either backscattered from the powered electrode in connection with the incoming energetic ion flux, or created by charge transfer collisions in the plasma sheath, may be excited in collisions with the background gas.