Patent ID: 6482263
Filing Date: 2002-11-19
Classification: C30B,Y10S,Y10T

Abstract:
A crystal puller for producing a monocrystalline ingot, the crystal puller comprising:a crucible for holding molten semiconductor source material; a heater in thermal communication with the crucible for heating the crucible to a temperature sufficient to melt the semiconductor source material held by the crucible; a pulling mechanism positioned above the crucible for pulling the ingot from the molten material held by the crucible; and a heat shield assembly adapted for location with respect to the crucible above the molten source material, the heat shield assembly having a central opening sized and shaped for surrounding the ingot as the ingot is pulled from the molten material, said heat shield assembly being generally interposed between the ingot and the crucible as the ingot is pulled from the source material, said heat shield assembly comprising an outer reflector having an inner surface and an outer surface in generally opposed, spaced relationship with a side wall of the crucible, and an inner reflector located inward of the outer reflector, the inner reflector being constructed of a material having a low emissivity and having an outer surface in generally opposed relationship with the inner surface of the outer reflector, at least one of the outer surface of the inner reflector and the inner surface of the outer reflector having a spacer projecting outward therefrom and adapted for contact relationship between the inner reflector and the outer reflector, the spacer spacing the outer surface of the inner reflector from the inner surface of the outer reflector to inhibit heat conduction from the outer reflector to the inner reflector.