Modeling particle formation during low-pressure silane oxidation: Detailed chemical kinetics and aerosol dynamics

A detailed chemical kinetic model is presented for silicon oxide clustering that leads to particle nucleation during low-pressure silane oxidation. Quantum Rice-Ramsperger- Kassel theory was applied to an existing high-pressure silane oxidation mechanism to obtain estimates for the pressure dependence of rate parameters. Four classes of clustering pathways were considered based on current knowledge of reaction kinetics and cluster properties in the Si-H-O system. The species conservation equations and a moment-type aerosol dynamics model were formulated for a batch reactor undergoing homogeneous nucleation and particle growth by surface reactions and coagulation. The chemical kinetics model was coupled to the aerosol dynamics model, and time-dependent zero-dimensional simulations were conducted. The effects of pressure and temperature were examined, and the main contributing processes to particle formation and growth were assessed, for conditions around 0.8 Torr, 773 K, and an initial oxygen-to-silane ratio of 15. (C) 2001 American Vacuum Society.