Three-dimensional simulation of a low-power microwave-excited microstrip plasma source

摘要

A low-power microwave-excited argon microstrip plasma source operated at 2.45GHz is studied by a three-dimensional fluid model. The electrodeless microwave-excited plasmas are produced in the gas channel with the gas pressures of 50 and 100 Torr at the input power of 2W. Simulations are performed by the plasma module of COMSOL Multiphysics (R). Results show that the electric field induced by the electromagnetic wave is concentrated in the neighborhood of the inner surface of gas channel under the microstrip line. The electromagnetic wave is restricted to transit from being propagating to evanescent in a very thin zone at which the electron density is equal to the critical density. The resonance zone is solved by adding an effective collision frequency to the momentum collision frequency. The governed ions are found to be atomic argon ions (Ar+) and molecular argon ions (Ar-2(+)) and the latter has a wider distribution. The three-body reactions to produce Ar-2(+) ions become important at high gas pressures. (C) 2016 The Japan Society of Applied Physics