An advanced multi-block method for the multiresolution modelling of EFG silicon tube growth

摘要

Edge-defined film-fed growth (EFG) is a widely used technique for the growth of polycrystalline silicon from its melt in the form of a ribbon or hollow tube of different shapes, e.g. octagon, nonagon, and circular. Growth of a large diameter silicon tube can help advance photovoltaic technology. A comprehensive two-dimensional axisymmetric numerical model, which accounts for heat/mass transfer, solidification and electromagnetic induction heating, has been developed to simulate the octagon silicon tube growth process. A single block, structured mesh is used to calculate the magnetic potential field generated by the radio-frequency induction heaters, and a non-matching multi-block method is developed to solve the energy equation with fine grids generated in the vicinity of the die-tip and silicon tube. Two sets of grid systems overlap each other and communicate by a high-order interpolation scheme. The proposed multi-block solution procedure developed in this paper satisfies the flux conservation at the block interface. Convergence and efficiency of the new method are studied and selected results of magnetic and temperature fields have been presented for the growth of octagonal silicon tubes of different sizes. Numerical predictions are in good agreement with the measurements. [References: 48]