Patent ID: 8147613
Filing Date: 2012-04-03
Classification: C30B,Y10T

Abstract:
1. A crystal puller for growing monocrystalline ingots according to the Czochralski method, the puller comprising: a housing; a crucible in the housing for containing a semiconductor source material melt, the melt having an upper surface; a side heater adjacent the crucible for heating the crucible; an elongate puller having an end adapted to connect to the ingot for pulling a growing ingot upward from the upper surface of the melt, a portion of the upper surface of the melt remaining exposed during growing of the ingot, the exposed upper surface portion having an area; an annular melt heat exchanger sized and shaped for surrounding the ingot and for being disposed adjacent the exposed upper surface portion of the melt, the heat exchanger including a heat source disposed to face the exposed upper surface portion of the melt, the heat source having an area for radiating heat to the melt sized at least 30% of the area of the exposed upper surface portion of the melt for controlling heat transfer at the upper surface of the melt, the melt heat exchanger being adapted to reduce heat loss at the exposed upper surface portion, the exposed upper surface portion of the melt allowing gases produced in the melt during heating thereof to exit the melt; and a reflector supporting the melt heat exchanger; wherein the reflector includes insulation interposed between the melt heat exchanger and the melt.