| 摘要 |
PURPOSE:To form a single crystal having uniform dislocation density distribution, by heating the single crystal during pulling up with an infrared heater provided near a furnace wall in pulling up the single crystal by the Czochralshi (CZ) method. CONSTITUTION:At least one infrared heater 10 is provided near a furnace wall at the top in a pulling up furnace, and the heater 10 is divided into the upper and lower parts with a paraboloidal reflecting plate 12 having a heat source, e.g. a tungsten coil 11, as a focus at the rear thereof. The opening angle (alpha) of the upper and lower parts is adjusted by a hingle 13. A single crystal 6 is heated with the infrared heater 10 while being pulled up from the surface of a raw material melt 3 by a seed crystal 5. Thus, the top central part of the single crystal 6 during the pulling up is heated to suppress the heat conduction in the axial direction of the crystal causing the dislocation in the central part, and dislocation in the central part of the crystal is reduced to give the aimed single crystal 6 having uniform dislocation density distribution. |
