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Validation of a Polysilicon Deposition Reactor

In this work, a CFD model for simulating industrial scale particle-fluid systems is used to model a fluidized bed reactor for the deposition of high-purity silicon from silane gas. The performance of these reactors is directly dependent on a large number of factors and parameters which make the design and optimiza- tion of the deposition reactors an engineering challenge. Using the reactor design and experimental data from work performed at the Jet Propulsion Laboratory as a basis for validation, the CFD model was found to accurately model the deposition rate, silicon fines production, and temperature distribution within a silane deposi- tion reactor. Additionally, the CFD model is demonstrated to be an effective tool for comparing different reactor designs on the basis of fluidization mode, reaction conversion, heat transfer, and particle mixing.

The deposition of solid silicon in a fluidized bed reactor (FBR) is an important step in the industrial production of high purity polysilicon, the primary substrate for modern electronic and photovoltaic components. In the silane-based process, a mixture of silane and hydrogen gas is forced through a gas distributor in the bottom of the reactor where it fluidizes silicon seed particles in the reactor. Upon entering the reactor, the silane gas reacts at the surface of the silicon seed particles and deposits additional silicon, resulting in the growth of the particle. After growing to the desired size, the silicon particles are removed from the reactor as product and are replaced with new seed particles.