Uncertainty and sensitivity, analysis of gas-phase chemistry in a CHF3 plasma

A global uncertainty and sensitivity analysis is performed for a detailed gas-phase reaction set in a CHF3 plasma. The goal of this paper is to ascertain the uncertainties in plasma reactor model results (plasma and radical densities) that originate from the uncertainties in the gas-phase chemistry database. We discuss the rates of reactions and their uncertainties. Comparisons with experimental data show that gas-phase rate uncertainties do not explain the disagreements at higher pressures (>30 mTorr). We also find that electron impact dissociation reactions of dominant neutrals are the largest sources of uncertainties. HF kinetics are also found to be critical in determining radical and feedstock gas densities. Relative ion densities are uncertain due to poor understanding of charge transfer mechanisms.