Crystal growth atmosphere for oxyorthosilicate materials production

Patent metadata

Field	Value
Publication number	US-10774440-B2
Application number	US-201916251118-A
Country	US
Kind code	B2
Filing date	Jan 18, 2019
Priority date	Nov 24, 2010
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A method of growing a rare-earth oxyorthosilicate crystal, and crystals grown using the method are disclosed. The method includes preparing a melt by melting a first substance including at least one first rare-earth element and providing an atmosphere that includes an inert gas and a gas including oxygen.

First claim

What is claimed is:

1. A method of growing a rare-earth oxyorthosilicate crystal, comprising:
preparing a melt by:
melting a first substance comprising at least one first rare-earth element;
melting at least one of: a substance comprising a group 2 element, a substance comprising a group 3 element, a substance comprising a group 6 element, or a substance comprising a group 7 element;
providing an atmosphere comprising an inert gas and a gas including oxygen, wherein the atmosphere comprises less than 300 parts per million of oxygen, the atmosphere being in contact with a surface of the melt; where the gas including oxygen is derived from the decomposition of one of an acid, a solid salt, a liquid salt, or a combination thereof; wherein the acid, the solid salt or the liquid salt comprises sodium carbonate, potassium carbonate, ammonium carbonate, copper carbonate, lanthanum carbonate, cesium carbonate, or a combination thereof; where the acid, the solid salt and/or the liquid salt is located in a vessel that contains the melt at the time of the decomposition;
providing a seed crystal;
contacting the surface of the melt with the seed crystal; and
withdrawing the seed crystal from the melt.

2. The method of claim 1 , wherein the gas including oxygen further comprises an additional oxygen-containing compound that disassociates to oxygen.

3. The method of claim 1 , wherein the inert gas has a thermal conductivity less than or equal to 150 mW/m-° K at the temperature used during crystal growth.

4. The method of claim 1 , wherein the gas including oxygen further comprises carbon dioxide.

5. The method of claim 1 , wherein the gas including oxygen further comprises at least one of carbon monoxide, oxygen, sulfur trioxide, phosphorous pentoxide, or an oxide of nitrogen.

6. The method of claim 5 , wherein the oxide of nitrogen comprises at least one of NO 2 , N 2 O, NO, N 2 O 3 , or N 2 O 5 .

7. The method of claim 1 , wherein the atmosphere comprises less than 200 parts per million of oxygen.

8. The method of claim 7 , wherein the inert gas comprises at least one of helium, argon, krypton, or xenon.

9. The method of claim 7 , wherein the inert gas comprises nitrogen.

10. The method of claim 1 , further comprising melting a second substance comprising a second rare-earth element, the second rare-earth element being incorporated into the rare-earth oxyorthosilicate crystal as a dopant.

11. The method of claim 10 , wherein the second rare-earth element is cerium.

12. The method of claim 1 , wherein the growing of the oxyorthosilicate crystal comprises growing a lutetium oxyorthosilicate crystal.

13. The method of claim 1 , wherein the acid, the solid salt or the liquid salt further comprises a nitrate, a phosphate, a manganate, a permanganate, a sulfate, a phosphate, or a combination thereof.

14. A method of decreasing oxygen vacancies incorporated in a rare-earth oxyorthosilicate crystal, the method comprising:
preparing a melt by melting a first substance comprising at least one first rare-earth element;
providing an atmosphere comprising an inert gas and a gas including oxygen, the atmosphere including less than 300 ppm oxygen, the atmosphere being in contact with a surface of the melt; where the gas including oxygen is derived from the decomposition of one of an acid, a solid salt, a liquid salt, or a combination thereof; wherein the acid, the solid salt or the liquid salt comprises sodium carbonate, potassium carbonate, ammonium carbonate, copper carbonate, lanthanum carbonate, cesium carbonate, or a combination thereof; where the acid, the solid salt and/or the liquid salt is located in a vessel that contains the melt at the time of the decomposition;
providing a seed crystal;
contacting the surface of the melt with the seed crystal; and
withdrawing the seed crystal from the melt.

15. The method of claim 14 , wherein the gas including oxygen further comprises an additional oxygen-containing compound that disassociates to oxygen.

16. The method of claim 14 , wherein the inert gas has a thermal conductivity less than or equal to 150 mW/m-° K at the temperature used during crystal growth.

17. The method of claim 15 , wherein the additional oxygen-containing compound comprises carbon dioxide.

18. The method of claim 14 , wherein the additional oxygen-containing compound comprises least one of carbon monoxide, oxygen, sulfur trioxide, phosphorous pentoxide, or an oxide of nitrogen.

19. The method of claim 18 , wherein the oxide of nitrogen comprises at least one of NO 2 , N 2 O, NO, N 2 O 3 , or N 2 O 5 .

20. The method of claim 14 , wherein the acid, the solid salt or the liquid salt further comprises a nitrate, a phosphate, a manganate, a permanganate, a sulfate, a phosphate, or a combination thereof.

Assignees

• Siemens Medical Solutions Usa Inc

Inventors

• Andreaco Mark S
• Cohen Peter Carl
• Carey Alexander Andrew

Classifications

• C09K11/77062

  Silicates · CPC title

• C09K11/77742 Primary

  Silicates · CPC title

• C30B15/02

  adding crystallising materials or reactants forming it in situ to the melt · CPC title

• C30B29/34

  Silicates · CPC title

• C30B15/04 Primary

  adding doping materials, e.g. for n-p-junction · CPC title