Osaka Titanium Co., Ltd.

Consarc Corporation

Sumitomo Sitix Co., Ltd.

Kyojiro Kaneko

Hideyuki Mizumoto

Jun-Ya Masuda

Teruoki Misawa

This invention aims at providing a silicon electromagnetic casting apparatus for accurate and easy manufacturing of high quality silicon ingots. This apparatus uses a furnace vessel, a conductive crucibleinstalled in the internal part of the furnace vesseland an induction coilinstalled on the outer circumference of the crucible. Constant pressure is maintained in the internal part of the furnace vesselusing a prescribed gas and the silicon inside the above mentioned crucibleis solidified after melting it by induction heating by applying voltage on the induction coil. The induction coilis made by placing 2 induction coilsandhaving different induction frequencies one above the other.

Method for electromagnetic casting of silicon in a conductive crucible using a highest- and lowest-disposed induction coil

A single crystal silicon is prepared by constructing a silicon melt reservoir of an induction coil coated on its internal surface with a layer of a high melting point insulating material and placing silicon raw material in the reservoir, heating the silicon raw material by application of an external heating means and by current applied to the induction coil which electromagnetically heats the silicon thereby forming a pool of molten silicon in the reservoir, actively cooling said induction coil, and drawing up a single crystal silicon rod from the molten silicon in the melt reservoir.

Method of manufacturing single-crystal silicon

A single crystal silicon is prepared by providing a silicon melt reservoir formed of an induction coil coated on its internal surfaces with a high melting insulating material which is subjected to an electromagnetic field which heats silicon placed in said melt reservoir, melting silicon in the melt reservoir by the application of the electromagnetic field and simultaneously depositing a scull layer of silicon on the inner surface of said reservoir, and pulling up a single crystal silicon rod from the silicon melt in the melt reservoir.

A method of producing single-crystal silicon is disclosed. Polycrystalline silicon rod is formed from polycrystalline silicon granules, lumps or a mixture thereof by continuous casting through electromagnetic induction. Then, silicon single cyrstal is grown from the polycrystalline silicon rod by the FZ method.

Method for producing silicon single crystal from polycrystalline rod

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.

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Osaka, Japan

Kyojiro Kaneko