Patent ID: 6579362
Filing Date: 2003-06-17
Classification: C30B,Y10T

Abstract:
A heat shield assembly for use in a crystal puller for growing a monocrystalline ingot from molten semiconductor source material, the crystal puller having a housing, a crucible contained in the housing 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 and a pulling mechanism positioned above the crucible for pulling the ingot from the molten source material held by the crucible, the heat shield assembly being disposed above the molten source material and having a central opening sized and shaped for surrounding the ingot as the ingot is pulled from the molten source material, said heat shield comprising:an inner shield panel constructed of a material substantially transparent to radiant heat from the ingot; and a heat exchanger at least partially surrounding the inner shield panel such that the inner shield panel is disposed generally intermediate the heat exchanger and the ingot as the ingot is pulled from the molten source material, the inner shield panel material being substantially transparent to radiant heat to permit radiant heat from the ingot to radiate through the shield panel to the heat exchanger for increasing the rate at which the ingot is cooled, thereby increasing the axial temperature gradient of the ingot as the ingot is pulled from the molten source material.