Numerical simulation and validation of reaction mechanism for the Siemens process in silicon production

The Siemens process is the most widely used silicon production routine for photovoltaic applications. However, the complicated chemistry in deposition reactor has not yet been fully understood, although there has been much research on it. In this paper, a modified reaction kinetic model was proposed to represent the gas phase and surface reactions based on the literature. The thermodynamic properties of gas phase components were re-evaluated by density functional theory since the reverse reaction rate of gas phase reaction is highly dependent on Gibbs energy change (ΔG). Most of our efforts were devoted to validating the reaction mechanism. The modified reaction model was analyzed and compared with published experimental data in two different reaction paths, deposition from trichlorosilane and etch from hydrochloride, respectively. The epitaxial growth rate could be predicted by the modified reaction model under a wide range of operating conditions. The results could provide a theoretical basis for possible computational fluid dynamics (CFD) simulations of industrial Siemens reactor in the future.