A chemical kinetic study of the oxidation of silane by nitrous oxide, nitric oxide and oxygen

Silane–nitrous oxide mixtures are widely used in the semi-conductor manufacturing industry. Although these mixtures are potentially hazardous, their explosive properties are not very well characterised. In the present study, the high temperature kinetics of highly argon diluted silane–nitrous oxide mixtures has been examined. The dynamics of oxygen atoms behind reflected shock waves has been studied by Atomic Resonance Absorption Spectroscopy at temperatures between 1725 and 2584 K and pressures from 231 to 601 kPa. In order to take into account the effect of silane molecule and silicon atom absorption at 130.5 nm, absorption cross section determinations have been performed. In our experimental conditions (compositions and observation times), steady state oxygen atom concentrations have been observed at low temperatures, after few hundreds of microseconds. At high temperatures, the initial fast increase of oxygen atom concentration was followed by a period of consumption. A kinetic model that reproduces very well the experimental absorption profiles has been developed. Important reactions have been underlined through sensitivity and reaction pathway analyses. Previous experimental results from the literature for the oxidation of silane by nitrous oxide, nitric oxide and oxygen behind reflected shock waves have also been compared to the results coming from the kinetic model.