Memc Electronic Materials, Inc.

Kirk D McCallum

Richard Joseph Phillips

Steven Lawrence Kimbel

Lee William Ferry

Richard G Schrenker

Larry E Drafall

A heat shield assembly is adapted for location within a crystal puller, with respect to a crucible, above molten source material held by the crucible in the puller. The heat shield assembly has a central opening sized and shaped for surrounding the ingot as the ingot is pulled from the molten material and is generally interposed between the ingot and the crucible as the ingot is pulled from the source material. The heat shield assembly comprises 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 is constructed of a material having a low emissivity and has 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 has a spacer projecting outward therefrom and adapted for contact relationship between the inner reflector and the outer reflector. The spacer spaces 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.

Heat shield assembly for crystal pulling apparatus

A crystal puller for growing monocrystalline silicon ingots according to the Czochralski method includes a housing and a crucible in the housing for containing molten silicon. The crucible has a side wall having a transmittance of at least about 80% generally throughout a light wavelength range of about 500 to about 2500 nanometers. A pulling mechanism is included for pulling a growing ingot upward from the molten silicon. In operation, polycrystalline silicon is charged to the crucible and the crucible is heated to melt the polycrystalline silicon for forming a molten silicon melt in the crucible. A seed crystal is then brought into contact with the molten silicon in the crucible and a monocrystalline silicon ingot is pulled up from the molten silicon.

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Warrenton, MO, United States of America

Kirk D McCallum