Device for manufacturing a crystalline material from a crucible having non-uniform heat resistance

Patent metadata

Field	Value
Publication number	US-9945046-B2
Application number	US-201214343004-A
Country	US
Kind code	B2
Filing date	Sep 3, 2012
Priority date	Sep 5, 2011
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The device forming a crucible for fabrication of crystalline material by directional solidification comprises a bottom and at least one side wall. The bottom presents a first portion having a first thermal resistance and a second portion having a second thermal resistance that is lower than the first thermal resistance. The second portion is designed to receive a seed for fabrication of the crystalline material. The bottom and side wall are at least partially formed by a tightly sealed part including at least one indentation participating in defining said first and second portions. The first portion is covered by a first anti-adherent layer having an additional first thermal resistance. The second portion may be covered by a second anti-adherent layer having an additional second thermal resistance that is lower than the first thermal resistance.

First claim

The invention claimed is:

1. A device forming crucible for fabrication of crystalline material by directional solidification comprising a bottom and at least one side wall wherein the bottom comprises:
a first portion presenting a first thermal resistance and a second portion presenting a second thermal resistance that is lower than the first thermal resistance,
the bottom and said at least one side wall being at least partly formed by a tightly sealed part comprising at least one indentation participating in defining said first and second portions,
wherein the first portion is covered by a first anti-adherent layer having a first face in contact with the bottom of the crucible and a second face designed to be in contact with the crystalline material, the first anti-adherent layer having an additional first thermal resistance measured between said first and second faces, and
wherein the second portion is covered by a second anti-adherent layer having a first face in contact with the bottom of the crucible and a second face designed to be in contact with the crystalline material, the second anti-adherent layer having an additional second thermal resistance that is lower than the first thermal resistance and measured between said first and second faces.

2. The device according to claim 1 , wherein the first anti-adherent layer has a thickness greater than a thickness of the second anti-adherent layer, the thicknesses being measured on the bottom of the crucible.

3. The device according to claim 1 , wherein the first anti-adherent layer and the second anti-adherent layer are made from the same material.

4. The device according to claim 1 , comprising a plurality of first and second portions with an alternation arrangement between the first and second portions from a first side wall to an opposite second side wall.

5. The device according to claim 1 , wherein an inner wall of the bottom of the tightly sealed part comprises an indentation representative of the second portion.

6. The device according to claim 1 , wherein an inner wall of the bottom of the tightly sealed part is flat.

7. A method for fabrication of a crucible according to claim 1 for directional solidification comprising a bottom and at least one side wall comprising:
forming a mask on the bottom of the crucible so as to define areas covered by the mask and uncovered areas,
depositing a first coating designed to form a first anti-adherent layer,
eliminating the mask,
depositing a second coating designed to form a second anti-adherent layer, and
annealing the first and second coatings to form the first and second anti-adherent layers.

8. The method according to claim 7 , wherein the mask is a sheet of paper.

9. The method according to claim 7 , wherein the coating is deposited by spraying.

10. The method according to claim 7 , wherein the coating is subjected to an oxidizing annealing so as to form the first anti-adherent layer oxidized on the inner surface of the bottom.

11. A system for solidification of crystalline material comprising:
a device forming crucible according to claim 1 ,
means for generating a thermal gradient inside the device forming crucible and
a counter-crucible made from a material presenting a lower thermal resistivity than a thermal resistivity of a material forming the bottom of the device forming crucible.

12. The system according to claim 11 , wherein the counter-crucible is located against the outer surface of the bottom of the device forming crucible, the counter-crucible presenting a bottom with an inner surface having a complementary shape to an outer surface of the bottom of the device forming crucible.

13. The system according to claim 11 , wherein the bottom of the counter-crucible has a constant thickness.

14. The system according to claim 11 , wherein the outer surface of the bottom of the device forming crucible is flat.

15. The system according to claim 11 , comprising a heat extractor facing the first portion and the second portion of the bottom of the device forming crucible.

16. The system according to claim 11 , comprising an additional thermal resistance arranged between the counter-crucible and a recess formed on the outer surface of the bottom of the device forming crucible so as to perform thermal conduction of the recessed area with the counter-crucible.

17. A method for fabrication of a crystalline material by directional solidification of a material in liquid phase in a device forming crucible of a system according to claim 11 , comprising:
providing the device forming crucible provided with a seed made from crystalline material made from a second crystalline material and arranged in such a way as to at least partially cover the second portion of the bottom of the device forming crucible, the device forming crucible being at least partially filled by a feedstock of material to be solidified,
generating a first thermal gradient in the device forming crucible so as to melt the material to be solidified, the seed remaining at least partially in solid state,
generating a second thermal gradient in the device forming crucible so as to solidify the material in the molten state from the seed.

18. The method according to claim 17 , wherein the seed is arranged in an indentation of the bottom of the device forming crucible.

19. The device according to claim 2 , wherein the first anti-adherent layer and the second anti-adherent layer are made from the same material.

20. The device according to claim 1 , wherein an inner wall of the bottom of the tightly sealed part comprises an indentation representative of the second portion, the indentation is formed by a blind hole.

21. The device according to claim 1 , wherein the bottom of the tightly sealed part is devoid of through hole.

Assignees

• Coustier Fabrice
• Camel Denis
• Jouini Anis
• Pihan Etienne
• Commissariat Energie Atomique

Inventors

• Coustier Fabrice
• Camel Denis
• Jouini Anis
• Pihan Etienne

Classifications

• C30B11/14

  characterised by the seed, e.g. its crystallographic orientation · CPC title

• C30B11/003 Primary

  Heating or cooling of the melt or the crystallised material · CPC title

• C30B29/06

  Silicon · CPC title

• C30B11/00 Primary

  Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method (C30B13/00, C30B15/00, C30B17/00, C30B19/00 take precedence; under a protective fluid C30B27/00) · CPC title

• Y10T117/1092

  Shape defined by a solid member other than seed or product [e.g., Bridgman-Stockbarger] · CPC title