SPUTTERING TARGET OF Li3PO4 AND METHOD FOR PRODUCING SAME

• US 20080173542A1
• Filed: 11/05/2007
• Published: 07/24/2008
• Est. Priority Date: 11/07/2006
• Status: Active Grant

• Current Assignee: Sapurast Research LLC
• Original Assignee: Infinite Power Solutions, Inc. (Apple Inc.)
• Inventors: Milonopoulou, Vassiliki, NEUDECKER, BERND J.
• Granted Patent: US 8,197,781 B2
• Time in Patent Office: Days
• US Class Current: 204/298.13
• CPC Class Codes: C23C 14/06 characterised by the coating material C23C14/0021 , C23C14/04 take precedence
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: Y10T 428/12618 Plural oxides

Abstract

A method of forming a lithium orthophosphate sputter target or tile and resulting target material is presented. The target is fabricated from a pure lithium orthophosphate powder refined to a fine powder grain size. After steps of consolidation into a ceramic body, packaging and degassing, the ceramic body is densified to high density, and transformed into a stable single phase of pure lithium orthophosphate under sealed atmosphere. The lithium orthophosphate target is comprised of a single phase, and can preferably have a phase purity greater than 95% and a density of greater than 95%.

Claims

1. A method of forming a target, comprising:

providing a lithium orthophosphate powder;

refining the powder to a grain size of equal to or less than 75 microns;

applying cold isostatic pressure processing to form a body;

degassing said body;

applying hot isostatic pressure processing to said body to form a dense body of single-phase lithium orthophosphate; and

finishing said dense body to form a target.

2. The method of claim 1, further comprising providing said target comprising a polycrystalline Li₃PO₄ phase.

3. The method of claim 1, further comprising providing said target comprising a single crystal type morphology of Li₃PO₄.

4. The method of claim 1, further comprising providing said target comprising a glassy Li₃PO₄ phase.

5. The method of claim 1, further comprising providing said target comprising a phase purity of greater than 95%.

6. The method of claim 1, further comprising providing said target comprising a phase purity of greater than 90%.

7. The method of claim 1, further comprising providing said target comprising a density of greater than 90%.

8. The method of claim 1, further comprising providing said target comprising a density greater than 95%.

9. The method of claim 1, further comprising providing said target comprising a density between 95% and 99%.

10. The method of claim 1, further comprising using said target inside a vacuum sputter deposition tool.

11. The method of claim 1, further comprising mixing small amounts of lithium oxide powder with said lithium orthophosphate powder prior to said refining the powder step.

12. The method of claim 1, further comprising refining said lithium orthophosphate powder to a mesh size of 250 mesh.

13. The method of claim 1, further comprising densifying the refined powder to approximately 50% density using the cold isostatic pressure process.

14. The method of claim 1, further comprising degasifying said body at a temperature between 400°

C. to 550°

C.

15. The method of claim 1, further comprising applying said hot isostatic pressure processing at pressures above 10 kpsi.

16. The method of claim 15, further comprising performing said hot isostatic pressure processing at a temperature less than about 850°

C. for about 2 hours.

17. A lithium orthophosphate target comprising a single phase comprising a phase purity greater than 90% and a density greater than 90%.

18. The target of claim 17, wherein the phase purity is greater than 95%.

19. The target of claim 17, wherein the density is greater than 95%.

20. The target of claim 17, wherein the density is between 95-99%.

21. The target of claim 17, wherein the phase purity is mote than 95%.

22. The target of claim 17, wherein the phase purity is more than 99%.

23. The target of claim 17, comprising a polycrystalline Li₃PO₄ phase.

24. The target of claim 17, comprising a single crystal type morphology of Li₃PO₄.

25. The target of claim 17, comprising a glassy Li₃PO₄ phase.