Two dimensional PIC-MCC calculation of a CCRF discharge in methane: transition between different modes

Summary form only given. Two dimensional capacitively coupled ratio frequency discharge in methane is simulated by fast PIC-MCC method. The results were obtained in pressure range 50-300 mTorr and voltage range 40-180 V for discharge frequency 13.56 MHz. The electron energy and electron-methane reaction rates spatial distributions show existence of two regimes of discharge glow: a) with active sheaths, when electrons are cold in the middle of discharge and the reactions proceed in electrode sheaths regions; b) with volume domination, when the electron energy is more uniform and the reactions take place in all discharge volume. The transition between these two modes is studied with variation of discharge voltage. The second regime is usually observed for low discharge voltages, and turns to the first one with voltage increasing. Besides, simulation of chemical reactions in methane plasma was also fulfilled to find the gas mixture composition in discharge volume. The results are in agreement with the known experimental data.