Apparatus and method employing focussed radiative heater for control of solidification interface shape in a crystal growth process
AssigneeGeneral Electric Company
InventorFarzin H. Azad
Life of this patent
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Abstract
An apparatus and method employing a radiative heater for control of a shape of a peripheral edge region of a solidification interface in a Czochralski crystal pulling process are provided wherein a radiative heater element, independently controllable from a primary heater, is provided above the upper level of the melt and of the solidification interface around the periphery of the crystal, the radiative heater element being selectively controlled to influence the shape of the solidification interface at the peripheral edge region thereof, in order to eliminate problems experienced with edge downturn at the peripheral edge region of the interface.
Claims16
Apparatus comprising:
- means for containing a melt of material to be grown into a crystal;
- first heater means for maintaining said melt in said melt-containing means in a desired bulk thermal condition;
- and
- second heater means for selectively controlling a shape of substantially an entire peripheral edge region of a solidification interface between said melt and said crystal, said second heater means being controlled independently of said first heater means, said second heater means being sized to fit within an upper portion of said melt containing means, and being configured to substantially surround said crystal being pulled, said second heater means further being disposed entirely above an upper level of said melt.
Apparatus comprising:
- means for containing a melt of material to be grown into a crystal;
- first heater means for maintaining a desired bulk thermal condition in said melt within said melt-containing means;
- and
- second heater means for selectively heating a target region, said target region comprising substantially an entire peripheral edge region of a solidification interface between said melt and said crystal, said second heater means being controlled independently of said first heater means, said second heater means extending around said target region at a height completely above and being spaced apart from an upper level of said melt, said second heater means further being so constructed and arranged to radiate heat toward said target region.
Dependencies are inferred from the claim text.