Bochum 2015 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 6: Poster Session - Diagnostics
P 6.16: Poster
Montag, 2. März 2015, 16:30–18:30, Foyer Audimax
Characterization of the E-H transition in inductively coupled RF oxygen discharges — •Thomas Wegner, Christian Küllig, and Jürgen Meichsner — Institute of Physics, University of Greifswald
The E-H transition of an inductively coupled radio frequency discharge in oxygen was studied using enhanced diagnostic methods.
Electrical quantities as well as plasma parameters were measured.
The plasma parameters strongly depend on RF power, coil voltage, coil current and total gas pressure.
Therefore, the positive ion saturation current, the line integrated electron and metastable density (O2(a1Δg)), the gas and electron temperature and the optical emission intensity of the atomic oxygen were investigated by Langmuir probe, 160 GHz microwave interferometry, VUV absorption and VIS emission spectroscopy, respectively.
The spatially resolved positive ion saturation current in the E-mode reveals a collision dominated RF sheath with a pressure dependence of the mean sheath thickness s∝ p−1/3.
During the E-H transition, the positive ion saturation current and the line integrated electron density are strongly increasing up to two orders of magnitude.
The gas temperature as well as the metastables density increase by a factor of two while the electron temperature halves during this transition.
Additonally, the heating mechanisms during the RF cycle change from the RF sheath heating and electrical field reversal in the E-mode to two heating phases in the plasma bulk due to the induced electric field in the H-mode.
//Funded by the DFG CRC/Transregio 24, project B5.