Numerical investigation of the kinetics and chemistry of rf glow discharge plasmas sustained in He, N2, O2, He/N2/O2, He/CF4/O2, and SiH4/NH3 using a Monte Carlo-fluid hybrid model

Abstract

Capacitively coupled radio-frequency (rf) glow discharges are standard sources in plasma assisted materials processing. Theoretical analyses of rf discharges have been hampered by the computational difficulty of simultaneously resolving nonequilibrium electron transport and plasma chemistry. We have developed a hybrid Monte Carlo-fluid simulation that can simulate nonequilibrium electron transport while executing with the speed of a fluid simulation. An electron Monte Carlo simulation (EMCS) is used to calculate the electron energy distribution (EED) as a function of position and phase in the rf cycle. Collision rates and transport coefficients are calculated from the EED and used in a self-consistent fluid model (SCFM) of charged particle behavior and a neutral chemistry/transport model. Electric fields from the SCFM are cycled back to the EMCS, and the process is iterated until convergence. All pertinent heavy particle (charged and neutral) reactions can be included as well as collisions of electrons with ions, excited states, and reaction products. The hybrid model is applied to a variety of gas mixtures of interest to materials processing.