Bonn 2000 – wissenschaftliches Programm
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P: Plasmaphysik
P 16: Plasmadiagnostik (Poster)
P 16.21: Poster
Mittwoch, 5. April 2000, 10:30–13:00, Aula
Langmuir probe measurements of reactive plasmas in an inductively coupled GEC reference cell — •S. V. Singh and H. Soltwisch — Institut für Experimentalphysik V, Ruhr-Universität Bochum
The Langmuir Probe measurement is relatively simple in non-reactive plasmas, but is rather complicated in reactive plasmas. In a reactive plasma, different chemically active materials are produced which can coat the probe surface. Probe contamination which changes the work function of the tip is the biggest problem associated with probe measurements in the reactive plasmas. A cylindrical probe system is used to investigate an inductively coupled rf (13.56 MHz) discharge in a GEC reference cell. An electrical heating technique is used for the cleaning of the tip. Different characteristic plasma parameters like floating potential, plasma potential, electron temperature, electron density and electron distribution function (EDF) are measured. The measurements have been made in Ar and admixtures with CH4 and O2, with the pressure ranging between 10 and 1000 Pa. The currents are calculated by the Orbital Motion Limited (OML)theory assuming collisionless movement in the space charge layer. The EDF is obtained from the second derivative curve using Druyvesteyn formula.