To improve mastery of the low pressure chemical vapor deposition semi-insulating polycrystalline silicon (SIPOS) SiOx process, a local kinetic model describing homogeneous and heterogeneous phenomena is used to analyze the influence of some key operating parameters and of the main geometrical reactor features on the process behavior. in particular, the gas hydrodynamics near an interwafer space is detailed, and the role of each chemical species involved in the deposit formation is investigated, with special attention paid to the two radicalar molecules silylene and silanone. This analysis has allowed us to explain the origins of the radial heterogeneities on wafers for each of the parameters investigated, thus opening possible ways of process optimization. This study demonstrates how efficient such a modeling tool can be for improving the existing process performances, or even for designing reactors. Such a mathematical approach is certainly a possible answer to the increasingly drastic industrial requirements of the microelectronic held. (C) 2001 The Electrochemical Society. All rights reserved.