Simulations of electromagnetic effects in large-area high-frequency capacitively coupled plasmas with symmetric electrodes: Different axial plasma density profiles

Abstract

In this paper, the electromagnetic effects are investigated in large-area high-frequency symmetric capacitive discharges by solving the Maxwell equations under two different axial plasma density profiles, i.e., the spatially uniform and the axial non-uniform density profiles. Simulation results show that the spatially uniform density profile underestimates the standing wave effect and overestimates the skin effect. Moreover, the electromagnetic effects are significantly affected by the frequency, sheath width, electron-neutral momentum transfer frequency, and plasma density. As the frequency increases, the surface wavelength is significantly reduced, and the standing wave effect becomes pronounced. An opposite result is obtained by increasing the sheath width. As the electron-neutral momentum transfer frequency increases, the radial damping of surface waves when they propagate from the radial edge to the center becomes prominent. As the plasma density increases, the discharge is dominated by the skin effect instead of the standing wave effect, due to the reduced skin depth.