A complete model of aerosol particle formation by thermal decomposition of
silane is presented, which includes all steps from aerosol precursor format
ion in the homogeneous reactions to particle coagulation. The model predict
s silane conversion, concentrations of gaseous intermediates (disilane, tri
silane, and others), size and concentration of aerosol particles, chemical
composition of aerosol particles (number of SiH and SiH2 groups in the part
icles). Additionally, we report measurements of aggregate fractal dimension
s on the basis of electron microscopy micrographs. These data are required
to link the chemical kinetic steps of the model with predictions about the
particle size. Calculated time dependencies of gaseous concentrations, part
icle size and concentration, particle chemical composition are in reasonabl
e agreement with the experimental data obtained in the present work as well
as in our earlier papers (Onischuk et al., 1997a.b, 1998a). The numerical
simulations showed that the relative contribution of vapor and clusters (co
ntaining not more than 10 silicon atoms) to the late of particle growth is
in the range of 20-30%. The contribution from the particles containing more
than 10(6) silicon atoms is in the range 70-80%. (C) 2000 Elsevier Science
Ltd. All rights reserved.