| 摘要 |
A pair of coils are arranged to surround a crucible for storing a melt. The axes of the coils are vertical and the melt is heated by a heater. When the coils are energized such that the magnetic fluxes thereof oppose each other along the axial direction, a magnetic field having an isomagnetic field distribution of an elliptical shape is formed. When the energization current is properly selected, a magnetic field for restricting thermal convection of the upper melt portion is formed, while, conversely, thermal convection of the lower melt portion occurs. When the melt surface level is lowered upon pulling of the single crystal, a magnetic field is controlled such that the boundary between the thermal convection restriction region and the thermal convection region is, similarly, lowered. Since thermal convection is restricted near the solid-liquid interface layer, the single crystal can be stably grown. In the lower melt portion, thermal convection is present such that the lower melt is stirred. The temperature of the melt is uniform, thereby manufacturing a uniform single crystal ingot of high quality. |
