Effect of inner crucible structure on oxygen transport and distribution in the continuous-feeding Czochralski growth of silicon crystal

Oxygen is one of the critical impurities in silicon crystal. Excessive oxygen leads to increased defects and reduced efficiency of solar cells. Therefore, reducing oxygen concentration is a key issue in silicon crystal. In this study, a global 2D model for the continuous-feeding Czochralski silicon crystal growth was established, considering the complex shapes of the corner and bottom of inner crucible, instead of using the simplification of cylindrical partition. Based on the model, numerical simulations were performed to investigate the effects of inner crucible diameter, corner shape, and bottom shape on flow, heat transfer and oxygen transport. The results indicate that the structure of inner crucible significantly affects the oxygen transport. With the decrease of inner crucible diameter, the oxygen at crystallization interface increases; with the increase of curvature radius of inner crucible corner, the oxygen at crystallization interface decreases; with the increase of curvature radius of inner crucible bottom, the oxygen at crystallization interface increases. The findings can provide guidance for the optimization of inner crucible structure for reducing oxygen concentration.