Numerical Simulation of Species Segregation and 2D Distribution in the Floating Zone Silicon Crystals

The distribution of dopants and impurities in silicon grown with the floating zone method determines the electrical resistivity and other important properties of the crystals. A crucial process that defines the transport of these species is the segregation at the crystallization interface. To investigate the influence of the melt flow on the effective segregation coefficient as well as on the global species transport and the resulting distribution in the grown crystal, we developed a new coupled numerical model. Our simulation results include the shape of phase boundaries, melt flow velocity and temperature, species distribution in the melt and, finally, the radial and axial distributions in the grown crystal. We concluded that the effective segregation coefficient is not constant during the growth process but rather increases for larger melt diameters due to less intensive melt mixing.

Automated summary

The distribution of dopants and impurities in silicon grown with the floating zone method is essential for determining the electrical resistivity and other important properties of the crystals. Segregation at the crystallization interface plays a crucial role in defining the transport of these species. A new coupled numerical model was developed to investigate the influence of melt flow on the effective segregation coefficient, global species transport, and resulting distribution in the grown crystal. The simulation results show that the effective segregation coefficient increases with larger melt diameters due to less intensive melt mixing during the growth process.