Method and device for controlling a crystal pulling apparatus

Abstract

The present invention relates to a method and device for controlling a crystal pulling apparatus while pulling a single crystal according to the Czochralski method. To this end, a crystal pulling apparatus is provided which has a vertically adjustable crucible, a heater surrounding at least a portion of the crucible, a pulling device operatively disposed over the crucible, and a control circuit operatively connected to the pulling device and the crucible. The heater is energized to form a molten mass in the crucible and the pulling device is actuated to pull a crystal from the molten mass. Through a control circuit, the crucible with the crystal can be adjusted in height relative to a heater, so that the upper edge of the heater juts to a greater or lesser degree over the crucible. The crystal pulling apparatus may also have a vertically adjustable funnel that surrounds the crystal and is positioned over and above the molten mass within the crucible leaving open a gap between a melt level of the molten mass and the lower edge of the funnel. This funnel is adjustable in height above the melt level by means of an actuator.

Dependencies are inferred from the claim text.