Kinetic modeling of particle formation during low-pressure silane oxidation and CVD

摘要

A detailed chemical kinetic model is presented for silicon oxide clustering that leads to particle nucleation during low-pressure silane oxidation. 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 reactors undergoing homogeneous nucleation, particle growth by surface reactions and coagulation, and particle transport by convection, diffusion and thermophoresis. The chemical kinetics model was self-consistently coupled to the aerosol dynamics model, and the reactor model. Both time-dependent zero-dimensional and steady one-dimensional simulations were conducted. The effects of various system parameters were examined, and the main contributing processes to particle formation and growth were assessed. The model has been tested against experimental measurements of particle formation and shows the correct pressure, temperature and concentrations at which particle inception occurs. A simple model to predict explosion in this system has been presented.