(200d) Modeling and Dynamic Simulation for Silicon Production through Silane Pyrolysis

Silicon has been the most important material in semiconductor industry and also the purest one among industrial products on large scale. As alternative energy has becoming an increasing concern nowadays, the mounting solar-grade silicon market is driving a new boom of the silicon production. Generally, the production of high purity silicon employs silicon vapor deposition, where silicon comes from silane pryolysis. This can be accomplished through two ways. One is to carry out the reaction between hydrogen and trichlorosilane in a tubular reactor, where silicon produced and deposited on an electrically heated silicon filament at a desired high temperature. The other way is to employ a fluidized bed reactor (FBR), where silicon deposits on silicon seed particles through silane pyrolysis at comparably low temperature.

To have an insight into these two reaction processes and so as to later on enhance the reactions performance, in terms of increasing process productivity meanwhile insuring product quality, rigorous dynamic simulations for these two reactions have been conducted in this work. It first revisits kinetics and mechanism of deposition of silicon by reduction of chlorosilane with hydrogen; then addresses three-dimensional simulation on deposition mechanism of three reversible reactions. Based on investigated kinetics and mechanism, as well as 3-D reactor modeling on silicon deposition reactor, the simulation for silicon deposition with the CFD software tool, FLUENT, is conducted. Based on validated simulation results with available experimental data, process optimization opportunities are also discussed.