Cold crucible

Patent metadata

Field	Value
Publication number	US-12228340-B2
Application number	US-202017429228-A
Country	US
Kind code	B2
Filing date	Feb 6, 2020
Priority date	Feb 7, 2019
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

A cold crucible usable in the field of high-temperature production of monocrystalline materials. The cold crucible includes: a cold cage which has sectors made of a material having good electrical conductivity and in which a charge is melted, and a cooling device with heat transfer fluid, configured to cool each segment of the cold cage from the inside. The cold crucible is essentially such that it further includes at least one device for generating a static magnetic field, each generating device being housed inside one of the sectors of the cold crucible. Each static magnetic field thus generated having the effect of slowing down the electromagnetic stirring of the molten charge, such that it is possible to produce monocrystalline ingots of significantly larger diameter than the diameter of the seed initiating their growth.

First claim

The invention claimed is:

1. A cold crucible comprising: a cage called cold cage comprising at least one sector made of material that is a conductor of electricity and into which a charge to be melted is to be introduced, and a cooling device comprising a heat-transfer fluid, the cooling device being configured to cool each sector of the cold cage, wherein the cold crucible further comprises at least one generation device for generating an electromagnetic field, each generation device being housed inside said at least one sector of the cold cage of the cold crucible, and wherein the electromagnetic field generated by the at least one generation device is such that it has a density substantially greater than 0.02 T, at a distance substantially greater than 2 mm from an edge of the at least one generation device oriented towards the inside of the cold cage.

2. The cold crucible according to claim 1 , wherein the at least one generation device is configured to generate a static magnetic field.

3. The cold crucible according to claim 1 , wherein the at least one generation device is configured to generate an electromagnetic field of sufficient density to be felt by the molten charge in the cold cage.

4. The cold crucible according to claim 1 , wherein the at least one generation device is housed within said at least one sector so as to be located, by the edge oriented towards the inside of the cold cage, at a distance substantially less than 12 mm from the molten charge in the cold crucible.

5. The cold crucible according to claim 1 , wherein the at least one generation device is housed in said at least one sector and is configured so as to be cooled by the cooling device of the cold crucible.

6. The cold crucible according to claim 1 , wherein the at least one generation device comprises at least one permanent magnet.

7. The cold crucible according to claim 5 , wherein, the at least one generation device comprises at least one permanent magnet, and the cooling device is configured to maintain that the at least one permanent magnet at a temperature strictly less than the Curie temperature of the at least one permanent magnet.

8. The cold crucible according to claim 6 , wherein said at least one permanent magnet is made of a material having an electrical resistivity greater than that of the material constituting the sectors of the cold cage.

9. The cold crucible according to claim 1 , wherein at least one generation device comprises a plurality of permanent magnets, the plurality of permanent magnets being arranged together so as to generate, at least towards the inside of the cold cage, a more powerful static magnetic field than the static magnetic field generated by each permanent magnet taken apart.

10. The cold crucible according to claim 9 , wherein the plurality of permanent magnets are arranged together in a configuration called Halbach configuration.

11. The cold crucible according to claim 1 , wherein the cold crucible further comprises a device for fastening and holding the sectors together, said device being configured so that the sectors fastened and held form at least part of the cold cage.

12. The cold crucible according to claim 1 , wherein a support portion of the at least one generation device is configured to support a plurality of permanent magnets and to form with inner walls of a housing of the at least one sector a circulation corridor for the heat-transfer fluid of the cooling device.

13. The cold crucible according to claim 1 , wherein the cold cage comprises the at least one sector comprises several sectors and the sectors of which are arranged in one of the following ways:
only two sectors opposite each other house a generation device;
only three sectors arranged substantially in rotational symmetry of order 3 house a generation device;
only four sectors arranged substantially in rotational symmetry of order 4 house a generation device;
one sector out of two adjacent sectors houses a generation device; or
each sector houses a generation device.

14. The cold crucible according to claim 1 , wherein with the cold cage comprising several sectors, the sectors are removable from one another.

15. The cold crucible according to claim 1 , wherein the at least one generation device comprises a first portion configured to generate the electromagnetic field and a second portion, called support portion configured to support the first portion of the at least one generation device and to cooperate closely with the housing of the at least one generation device in said at least one sector.

16. A cold crucible comprising:
a cage called cold cage comprising at least one sector made of material that is a conductor of electricity, and into which a charge to be melted is to be introduced, and
a cooling device involving a heat-transfer fluid, the cooling device being configured to cool
each sector of the cold cage,
wherein the cold crucible further comprises at least one device for generating an electromagnetic field, each generation device being housed inside at least one sector of the cold cage of the cold crucible; and
wherein each sector whose housing is free of a generation device houses at least one among: a ferrite-based material, a measurement probe or a device for modifying or analysing the molten charge.

Assignees

• Inst Polytechnique Grenoble
• Centre Nat Rech Scient
• Univ Grenoble Alpes

Inventors

• Zaidat Kader
• Garnier Christian
• Hasan Ghatfan

Classifications

• H05B6/42

  Cooling of coils · CPC title

• H05B6/24 Primary

  Crucible furnaces (H05B6/30 takes precedence) · CPC title

• F27B2014/108

  Cold crucibles (transparent to electromagnetic radiations) · CPC title

• C30B35/002

  Crucibles or containers · CPC title

• C30B29/06

  Silicon · CPC title