Apparatus for casting silicon with gradual cooling
AssigneeOsaka Titanium Co., Ltd.
InventorsKyojiro Kaneko, Jun-Ya Masuda
Life of this patent
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Abstract
For the continuous casting of silicon, an electrically conductive bottomless crucible is circumferentially divided by axial slits and is positioned within an electrical induction coil. The slits form circumferential gaps of between 0.3 mm and 1.0 mm and the inner wall of the crucible is inclined by between 0.4.degree. and 2.0.degree., so that the crucible expands in the downstream direction of movement of the silicon. In order to reduce the temperature gradient of the solidified silicon to between 20.degree. C./cm and 100.degree. C./cm, an additional heating element is disposed downstream of the boundary surface between the molten and solidified silicon. The crucible may be cooled by forming the crucible as a double walled cylinder and flowing a coolant therethrough.
Claims20
An apparatus for casting silicon, comprising:
- an electrically conductive bottomless crucible, at least an axial part of said crucible being divided into a plurality of circumferentially spaced parts;
- an electrical induction coil surrounding said crucible, whereby silicon continuously moving through said crucible may be melted and subsequently solidified;
- and
- means for heating said solidified silicon, said means for heating being disposed downstream of a boundary surface level between said molten and solidified silicon, in a direction of movement of said silicon, whereby a temperature gradient in said solidified silicon in the direction of movement is reduced.
Dependencies are inferred from the claim text.