Role of coil-crucible geometry in Czochralski bismuth germanate (BGO) crystal growth process: a thermal stress analysis

A numerical model of 2D finite element in a steady-state level was developed for the electromagnetic field, heat distribution, and thermal stress expansion in an oxide Czochralski crystal growth system. The extended model was employed to compare the impact of different geometries of induction coils and crucibles in the growth process. Analysis of the results emphasizes the potential of the modified geometries in alteration of the electromagnetic field and heat distribution. Consequently, the optimization of crystal/melt interface shape, thermal stress accumulation, and distribution in the growing crystal can be achieved. Finally, the proposed approaches for thermal stress calculations were compared. The outcomes showed a qualitative agreement between two methods of thermoelastic stress analysis in the calculation of stress distribution in BGO crystal.