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AssigneeMEMC Electronic Materials, Inc.
InventorsRichard G. Schrenker, William L. Luter
Estimating the term…
An electrical resistance heater for use in a crystal puller used for growing monocrystalline silicon ingots according to the Czochralski method comprises a heating element sized and shaped for disposition in the housing of the crystal puller around the crucible for applying heat to the crucible and silicon therein. The heating element includes heating segments connected together in an electric circuit. The segments have upper and lower sections and are arranged relative to each other so that when disposed around the crucible containing molten silicon the upper sections are disposed generally above a horizontal plane including the surface of the molten silicon and the lower sections are disposed generally below the horizontal plane. The upper sections are constructed to generate more heating power than the lower sections thereby to reduce a temperature gradient between the molten silicon at its surface and the ingot just above the surface of the molten silicon. The upper sections have a thickness substantially equal to the thickness of the lower sections and have a width substantially less than the width of the lower sections. The cross-sectional area of the upper sections is everywhere less than the cross-sectional area of the lower sections.
An electrical resistance heater for use in a crystal puller used for growing monocrystalline silicon ingots according to the Czochralski method, the crystal puller having a housing, a crucible in the housing for containing molten silicon and a pulling mechanism for pulling a growing ingot upward from the molten silicon, the heater comprising a heating element sized and shaped for disposition in the housing of the crystal puller around the crucible for applying heat to the crucible and silicon therein, the heating element including heating segments connected together in an electric circuit, the segments having upper and lower sections and being arranged relative to each other so that when disposed around the crucible containing molten silicon the upper sections are disposed generally above a horizontal plane including the surface of the molten silicon and the lower sections are disposed generally below the horizontal plane, the upper sections being constructed to generate more heating power than the lower sections thereby to reduce a temperature gradient between the molten silicon at its surface and the ingot just above the surface of the molten silicon, the upper sections having a thickness substantially equal to the thickness of the lower sections and having a width substantially less than the width of the lower sections, the cross-sectional area of the upper sections being everywhere less than the cross-sectional area of the lower sections.
An electrical resistance heater for use in a crystal puller used for growing monocrystalline silicon ingots according to the Czochralski method, the crystal puller having a housing, a crucible in the housing for containing molten silicon and a pulling mechanism for pulling a growing ingot upward from the molten silicon, the heater comprising a heating element sized and shaped for disposition in the housing of the crystal puller around the crucible for applying heat to the crucible and silicon therein, the heating element including heating segments connected together in an electric circuit, the segments having upper and lower sections and being arranged relative to each other so that when disposed around the crucible containing molten silicon the upper sections are disposed generally above a horizontal plane including the surface of the molten silicon and the lower sections are disposed generally below the horizontal plane, the upper sections being constructed to generate more heating power than the lower sections thereby to reduce a temperature gradient between the molten silicon at its surface and the ingot just above the surface of the molten silicon, the upper sections having a thickness substantially equal to the thickness of the lower sections and having a width substantially less than the width of the lower sections, the cross-sectional area of the upper sections being everywhere less than the cross-sectional area of the lower sections, connection of the heating segments defining a serpentine configuration having circumferentially alternating upward extending slots and downward extending slots spacing unconnected portions of the heating segments, the upward extending slots extending substantially from the bottom of the heating element up to connected upper sections of adjacent heating segments, the downward extending slots extending substantially from the top of the heating element down to connected lower sections of adjacent heating segments, at least a portion of each downward extending slot having a width substantially greater than the width of each upward extending slot.
Dependencies are inferred from the claim text.