Ion Energy Distribution Functions in Magnetized Capacitively Coupled RF Discharges

Jan Trieschmann, Mohammed Shihab, Daniel Szeremley, Abd Elfattah Elgendy, Sara Gallian, Denis Eremin, Ralf Peter Brinkmann, Thomas Mussenbrock

40th IEEE In­ter­na­tio­nal Con­fe­rence on Plas­ma Sci­ence (ICOPS) & Pulsed Power and Plasma Science (PPPS) 2013, San Francisco (California), USA, 17-21 June


Abstract

The influence of a spatially inhomogeneous static magnetic field on the characteristics of capacitively coupled radio frequency discharges is investigated. In particular, the focus is placed on the sheath dynamics and the ion energy distribution functions (IEDFs) of ions impinging the electrodes. For this study we employ two different kinetic models. The first is the Particle- in-Cell (PIC) code yapic [1], which takes into account the entire discharge; the second code is the Ensemble-in-Spacetime (EST) model [2] which resolves the plasma boundary sheath only. We make a comparison of the two models by using the sheath volt- age and the ion flux through the sheath calculated with PIC as input for EST. [3] We find excellent agreement of the IEDFs cal- culated with both methods. In addition, good qualitative agree- ment of the sheath dynamics is observed. However, a quantita- tive discrepancy between the models can be identified, caused by different collision processes implemented in both models. While it is found that electrons are strongly affected by the ap- plied magnetic field, ions are only indirectly influenced in terms of the asymmetry of the discharge. In addition, we find that EST may be used as an efficient postprocessing tool to obtain the IEDFs even in magnetized cases, in particular if only sim- plified (i.e., global or fluid-dynamic) models are available.

[1] M.M. Turner, A. Derzsi, Z. Donko ?, D. Eremin, S.J. Kelly, T. Lafleur, and T. Mussenbrock, Phys. Plasmas 20, 013507 (2013). [2] M. Shihab, D. Ziegler, and R.P. Brinkmann, J. Appl. Phys. 45, 185202 (2012). [3] J.Trieschmann,M.Shihab,D.Szeremley,A.E.Elgendy,S. Gallian, D. Eremin, R.P. Brinkmann and T. Mussenbrock, J. Phys. D: Appl. Phys. 46, 084016 (2013).

Tags: capacitive, ccp, distribution, energy, IEDF, ion, magnetized, plasma