Sputtering target of Li 3 PO 4 and method for producing same

• US 8,197,781 B2
• Filed: 11/05/2007
• Issued: 06/12/2012
• Est. Priority Date: 11/07/2006
• Status: Active Grant

• Current Assignee: Sapurast Research LLC
• Original Assignee: Infinite Power Solutions, Inc. (Apple Inc.)
• Inventors: Neudecker, Bernd J., Milonopoulou, Vassiliki
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US11/935,000
• Publication Number:
  US 20080173542A1
• Time in Patent Office: 1,681 Days
• Field of Search: 423/312, 423/313, 428/702, 428/633, 117/941, 204/298.13
• US Class Current: 423/312
• 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 sputter target comprising a single phase comprising a phase purity greater than 90% and a density of greater than 90%.

2. The method of claim 1, wherein said sputter target comprises a polycrystalline Li₃PO₄ phase.

3. The method of claim 1, wherein said sputter target comprises a single crystal morphology of Li₃PO₄.

4. The method of claim 1, wherein said sputter target comprises a glassy Li₃PO₄ phase.

5. The method of claim 1, wherein said sputter target comprises a phase purity of greater than 95%.

6. The method of claim 1, wherein said sputter target comprises a density greater than 95%.

7. The method of claim 1, wherein said sputter target comprises a density between 95% and 99%.

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

9. 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.

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

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

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

C. to 550°

C.

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

14. The method of claim 13, further comprising performing said hot isostatic pressure processing at a temperature less than about 850°

C. for about 2 hours.

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

16. The target of claim 15, wherein said phase purity is greater than 95%.

17. The target of claim 15, wherein said density is greater than 95%.

18. The target of claim 15, wherein said density is between 95% and 99%.

19. The target of claim 15, wherein said phase purity is between 95% and 99%.

20. The target of claim 15, wherein said phase purity is greater than 99%.

21. The target of claim 15, comprising a polycrystalline Li₃PO₄ phase.

22. The target of claim 15, comprising a single crystal morphology of Li₃PO₄.

23. The target of claim 15, comprising a glassy Li₃PO₄ phase.