PARTICLE SIMULATION OF RADIOFREQUENCY PLASMA DISCHARGES OF METHANE FOR CARBON-FILM DEPOSITION

Particle-in-cell Monte Carlo (PIC/MC) simulations of capacitively coup led radio-frequency (RF) glow discharges were carried out for low pres sure CH4 plasmas. The present computational scheme includes the motion s and collisions of both neutral and charged particles. The CH4 plasma is modeled by combining a one-dimensional PIC/MC method with a polyat omic particle collision scheme. The model considers the motions of CH4 , CH4+, CH3, C2H5, H-2, H, and electrons. Space and time dependent res ults show ionization rate is high at the sheath region. The dissociati on rate of CB is found to be high at the sheath as well as in the plas ma bulk. Deposition rate of carbon him is calculated by sampling impin ging particles at the powered electrode, The calculations show that ne utral radicals are the major depositing species for the cases studied, Ion energy impinging to the electrode was found to be strongly depend ent on the ''imposed'' de bias (as opposed to self-bias) voltage for a given RF voltage, Deposition rate was found to be almost independent of the ''imposed'' de bias voltage as the RF voltage remained constant .