Numerical Analysis on Substrate-Incident Carbon Flux in Low-Pressure Radio-Frequency CH₄ Plasmas for Deposition of Diamond-Like Carbon Films

Abstract

Capacitively-coupled hydrocarbon (CH₄) plasmas for deposition of diamond-like carbon films have been simulated using a self-consistent one-dimensional fluid model, incorporating the mass balance equations for electrons, ions, radicals and non-radicals, the electron energy balance equation, coupled with the Poisson equation. Despite of low-pressure CH₄ gas condition, many positive-ion species, such as C₂H₄⁺, CH₄⁺, C₂H₂⁺, CH₅⁺ etc., have been found in the plasmas. The non-radical neutrals, such as C₂H₄, C₃H₈, C₂H₂ and C₂H₆, have also found with higher densities comparable to the source gas density. This result indicates that this complexity of background gas in CH₄ plasmas is strongly affected to the electron energy distribution function, which is important for the determination of plasmas properties.