Berlin 2014 – scientific programme

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P: Fachverband Plasmaphysik

P 6: Theory and Modelling

P 6.1: Talk

Monday, March 17, 2014, 16:30–16:45, SPA HS202

Analysis of electrode asymmetry effects in oxygen ccrf discharge plasmas — •Igor Sheykin, Markus M. Becker, and Detlef Loffhagen — INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald

Capacitively coupled radio frequency (ccrf) discharges between plane-parallel electrodes are generally asymmetric, where effects of asymmetry are especially important at lower pressures. In modelling studies of such discharges a symmetric geometry is usually used. In the present contribution a time-dependent, spatially one-dimensional fluid model containing continuity equations for the densities of electrons and relevant heavy particles, the electron energy balance equation and Poisson’s equation and taking the discharge asymmetry in accordance with [1] is used to analyse the influence of the discharge asymmetry on the plasma parameters. First results are discussed for oxygen plasmas at the experimental conditions given in [2] for a pressure of 30 Pa and applied voltages between 200 and 500 V at a frequency of 13.56 MHz. The modelling results show that the calculated bias voltages are in good agreement with measured ones. The charged particles obtained by modelling have similar distributions over the gap in symmetric and asymmetric discharges, but their shapes differ more with larger asymmetry of the discharge particularly in front of the electrodes.

The work was supported by Deutsche Forschungsgemeinschaft within SFB TRR 24.

[1] M. S. Barnes et al., J. Appl. Phys. 61 (1987) 81

[2] C. Küllig et al., Plasma Sources Sci. Technol. 19 (2010) 065011