PolySim. Software Overview.
PolySim is a powerful tool for design and optimization of reactors for polycrystalline silicon deposition from chlorosilanes by Siemens process. The tool is largely oriented to engineers and researchers and does not require expertise in Computational Fluid Dynamics from the users. The unique features of the tool are built-in chemical and heat reactor models combined with simple and convenient Graphical User Interface (GUI), which works in “grower-friendly” terms similar to those used in real reactor operation, minimizing the possible errors and saving user time needed to set-up the problem.
The growth simulation includes modeling of numerous physicochemical processes such as turbulent heat and mass transfer, radiative heat transfer, gas-phase and surface chemical reactions, and electrical heating of the silicon rods. The software employs chemical models involving gas-phase precursor decomposition and interaction and an original surface chemistry model. The approach suggested allows description of the chemical processes at the gas-solid interfaces in a wide range of operating conditions.
The PolySim GUI includes everything required for the problem specification, solution control, and visualization of the results. The program allows the user to find almost all the reactor characteristics depending on varying operating conditions and main characteristics of reactor design. It is also possible to evaluate the effect of the conditions non-uniformity on the growth of the different rod sections. For modeling the whole growth process, a number of separate points for different rod diameters are computed, and then the instantaneous reactor characteristics are time-integrated. The solution residuals are visualized by the GUI, allowing easy convergence control. The computed characteristics include reactor productivity, energy consumption per 1 kg of silicon, silicon conversion, electrical current parameters, gas flow rates, rod center temperature, gas depletion at the growth surface, the flow criteria, the energy consumption content. Run-time and post-processing visualization is available within the GUI, presenting dependencies of the input parameters and computed characteristics.
Figure 2. PolySim results: dependence of energy cost on temperature and pressure