Chemical modeling of a high-density inductively-coupled plasma reactor containing silane

Abstract

We carried out the modeling of chemical reactions in a silane-containing remote Inductively Coupled Plasma Enhanced Chemical Vapor Deposition (ICPECVD) system, intended for deposition of silicon, silicon oxide, and silicon nitride layers. The required electron densities and Electron Energy Distribution Functions (EEDF) were taken from our earlier Langmuir-probe measurements. The EEDF exhibited a fraction (0.5%) of fast electrons in the energy range between 20 and 40 eV, strongly deviating from Maxwell–Boltzmann (MB) distribution. We considered 16 electron impact dissociation/ionization reactions and 26 secondary reactions for homogeneous propagation of plasma species. We noticed a significant difference (orders of magnitude) between the concentrations of the species obtained using experimental EEDFs and MB energy distributions, pointing to the importance of the fast electron tail. For silicon oxide films, a qualitative agreement between the radical densities in plasma at different total pressures and the deposition rate was observed.