A kinetics and transport model of dichlorosilane chemical vapor deposition

Computational fluid dynamics is employed to examine silicon growth on a (100) surface in a dichlorosilane-hydrogen chemical vapor deposition (CVD) system. Species balaces are solved in conjunction with mass, momentum, and energy balances to predict growth rates in the system. The gas-phase mechanism includes the DCS decompositions SiH₂Cl₂ → SiCl₂ + H₂ and SiH₂Cl₂ → SiHCl + HCl and the surface mechanism accounts for adsorption and growth from SiCl₂, SiHCl, and SiH₂Cl₂. Arrhenius plot from the model show good agreement with experiment for overall growth rates at low DCS inflow concentrations but over predicts growth rates for higher DCS inflow concentrations. A sensitivity analysis is presented in the form of Arrhenius plot for several of the more important reactions included in the mechanism. The model suggests that growth rates are very sensitive to the gas-phase decomposition of SiH₂Cl₂ and the dissociative adsorption of SiH₂Cl₂ and not very sensitive to the dissociative adsorption of H₂ and the activation energy for the surface growth from adsorbed SiCl and H by elimination of HCl.