Adam Obrusník, Zdeněk Bonaventura

Studying a low-pressure microwave coaxial discharge in hydrogen using a mixed 2D/3D model

Journal of Physics D 48 (2015) 065201

This work presents a numerical model of hydrogen plasma in a microwave coaxial discharge at low pressure (25 to 25 Pa). The model is a hybrid model in terms of geometry as it combines three-dimensional geometry for the electromagnetic field and two-dimensional geometry for the transport equations. The model is validated against experimental results available in literature and, where possible, simulations of comparable discharges. The model shows very good experimental agreement in the relevant pressure range. A parametric study with respect to pressure is carried out and it is observed that the plasma contracts towards the antenna with increasing pressure. Increasing the pressure also influences the abundance of H⁺ ions but on the other hand it has little impact on hydrogen dissociation degree and electron temperature. Furthermore, the uniformity of the plasma above the substrate holder is analyzed. It is observed that at pressures over 150 Pa, the plasma gets non-uniform in the direction parallel to the antennas. Finally, the uniformity of particle and energy fluxes to the substrate holder are analysed. Knowing the fluxes is especially useful for the material applications of the device.

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DOI: 10.1088/0022-3727/48/6/065201

You can also contact one of the authors: adamobrusnik@physics.muni.cz