Low-pressure chemical vapor deposition of semi-insulating polycrystalline silicon thin films II. Theoretical local analysis of the process

To improve mastery of the low pressure chemical vapor deposition semi-insul ating polycrystalline silicon (SIPOS) SiOx process, a local kinetic model d escribing homogeneous and heterogeneous phenomena is used to analyze the in fluence of some key operating parameters and of the main geometrical reacto r features on the process behavior. in particular, the gas hydrodynamics ne ar an interwafer space is detailed, and the role of each chemical species i nvolved in the deposit formation is investigated, with special attention pa id to the two radicalar molecules silylene and silanone. This analysis has allowed us to explain the origins of the radial heterogeneities on wafers f or each of the parameters investigated, thus opening possible ways of proce ss optimization. This study demonstrates how efficient such a modeling tool can be for improving the existing process performances, or even for design ing reactors. Such a mathematical approach is certainly a possible answer t o the increasingly drastic industrial requirements of the microelectronic h eld. (C) 2001 The Electrochemical Society. All rights reserved.