Investigation of Oxygen Behavior under Different Melt Flow, Diffusion Boundary Layer, and Crystal-Melt Interface in a 300 mm Silicon Crystal Growth with Cusp Magnetic Field

Abstract

The silicon single crystals for semiconductor application are usually grown by the Czochralski (CZ) method. In this paper, we studied a 300 mm Czochralski silicon crystal grown with a cusp magnetic field to be used for an insulated gate bipolar transistor (IGBT). Different positions of the zero-Gauss plane (ZGP) under a cusp magnetic field were simulated and compared to numerical analysis. We investigated three factors that affected the oxygen concentration in the crystal, including (1) melt convection, (2) melt flow velocity near the quartz crucible wall, and (3) the diffusion boundary layer. We also studied the shape of the solid/liquid interface at the same time. The simulation results show that a change in the ZGP of the cusp magnetic field (CMF) strongly affects the convection in the melt, which leads to a difference in the thickness of the boundary layer near the wall of the quartz crucible. We investigated the relationship of the ZGP, convection in the melt, and the thickness of the boundary layer. In this way, we determined how to reduce oxygen diffusing into the melt and finally into the crystal. After simulation results were obtained, we pulled single crystals under the three configurations. The results show that the experimental data of the oxygen content and shape of the solid/liquid interfaces are consistent with the simulation results.