2-D simulation of dual frequency capacitively coupled helium plasma, using COMSOL multiphysics

A two-dimensional (2D) self-consistent fluid simulation of dual frequency capacitively coupled radio discharges of helium plasma is presented. The model solves the continuity equations for charged species and the electron energy balance equation, coupled with Poisson´s equation by finite element method, using COMSOL Multiphysics software. In this study, the low frequency (LF) is set to 13.56 MHz with low frequency voltage of 250 V and the high frequency (HF) is set to 54.24 MHz with high frequency voltage of 100 V. The simulations yield the two-dimensional profiles of plasma components as well as the charge densities, electric field, electron temperature and ionization rate between symmetric parallel plate electrodes. The effects of low and high frequency sources parameters such as frequency values and applied voltage amplitude on the discharge characteristics are investigated. It is shown that the increase of the HF frequency causes a moderate increase of electron temperature and plasma density, whereas, the increase of the LF potential produced an increase in the plasma potential, the voltage of the sheath and the ion energy.