Patent ID: 6146459
Filing Date: 2000-11-14
Classification: C30B,Y10S,Y10T

Abstract:
A Czochralski puller for growing monocrystalline silicon ingots comprising:an enclosure;a crucible in the enclosure that holds a silicon melt;a seed holder in the enclosure, adjacent the crucible;a heater in the enclosure, surrounding the crucible;a heat pack in the enclosure, surrounding the heater;a heat shield between the crucible and the seed holder;a cooling jacket between the heat shield and the seed holder; andmeans for pulling the seed holder away from the crucible to thereby pull a monocrystalline silicon ingot from the silicon melt, the monocrystalline silicon ingot having an axis and a cylindrical edge, the silicon melt and the ingot defining an ingot-melt interface therebetween;at least one of the position of the heat shield, the configuration of the heat shield, the position of the heater, the configuration of the cooling jacket, the position of the crucible, the configuration of the heat pack and the power that is applied to the heater being selected to produce a temperature gradient at the ingot-melt interface that is greater than about 2.5 degrees Kelvin per millimeter at the axis and that is also at least about equal to the temperature gradient at a diffusion length from the cylindrical edge.