Doped aluminum nitride crystals and methods of making them

• US 9,525,032 B2
• Filed: 03/26/2014
• Issued: 12/20/2016
• Est. Priority Date: 12/02/2005
• Status: Active Grant

• Current Assignee: Crysal IS, Inc.
• Original Assignee: Crystal IS, Inc. (Asahi Kasei Corporation)
• Inventors: Slack, Glen A., Schowalter, Leo J.
• Primary Examiner(s): Kunemund, Robert M
• Application Number:
  US14/225,999
• Publication Number:
  US 20140231725A1
• Time in Patent Office: 1,000 Days
• US Class Current: 1/1
• CPC Class Codes: C30B 23/00 Single-crystal growth by condensing evaporated or sublimed materials
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/2258 Diffusion into or out of AIIIBV compounds
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/207 further characterised by the doping material H01L29/2006 takes precedence
• CPC Class Codes: H01L 33/325 characterised by the doping materials

Abstract

Fabrication of doped AlN crystals and/or AlGaN epitaxial layers with high conductivity and mobility is accomplished by, for example, forming mixed crystals including a plurality of impurity species and electrically activating at least a portion of the crystal.

Claims

1. An extraction-activated bi-doped p-type AlN crystal doped with a plurality of V_AlSi₂N₃ complexes.

2. The AlN crystal of claim 1, wherein a mobility thereof is greater than approximately 25 cm² V⁻

1 s<sup>−

1</sup> at room temperature.

3. The AlN crystal of claim 1, wherein a conductivity thereof is conductivity greater than approximately 10⁻

5 Ω

<sup>−

1</sup> cm<sup>−

1</sup> at room temperature.

4. The AlN crystal of claim 1, wherein a conductivity thereof is conductivity greater than approximately 3×

10<sup>−

3</sup> Ω

<sup>−

1</sup> cm<sup>−

1</sup> at room temperature.

5. The AlN crystal of claim 1, wherein a concentration of V_AlSi₂N₃ complexes within the AlN crystal is larger than a concentration of V_AlSi₃N₄ complexes within the AlN crystal.

6. The AlN crystal of claim 1, wherein the AlN crystal is disposed within a semiconductor device.

7. The AlN crystal of claim 1, wherein a thickness thereof is at least approximately 0.1 mm and a diameter thereof is at least approximately 1 cm.

8. The AlN crystal of claim 7, wherein the diameter is at least approximately 2 cm.

9. The AlN crystal of claim 1, wherein dimensions thereof are at least 2 mm by 2 mm by 1 mm.

17. The AlN crystal of claim 1, further comprising an epitaxial layer disposed thereover.

18. The AlN crystal of claim 17, wherein the epitaxial layer comprises at least one of AlN, GaN, InN, or an alloy or mixture thereof.

19. The AlN crystal of claim 17, wherein the epitaxial layer comprises Al_xGa_1-xN.

20. The AlN crystal of claim 19, wherein x is greater than 0.5.

10. A bi-doped, p-type AlN crystal having a mobility greater than approximately 25 cm² V⁻

1 s<sup>−

1</sup> at room temperature, the bi-doped AlN crystal being doped with both (i) a donor species comprising 0 and (ii) an acceptor species comprising C, wherein (i) both the donor species and the acceptor species occupy anion lattice sites in the AlN crystal and (ii) at least portions of the donor species and the acceptor species are present within the AlN crystal as Al₂OC compounds.

11. The AlN crystal of claim 10, wherein a conductivity thereof is conductivity greater than approximately 10⁻

5 Ω

<sup>−

1</sup> cm<sup>−

1</sup> at room temperature.

12. The AlN crystal of claim 10, wherein a conductivity thereof is conductivity greater than approximately 3×

10<sup>−

3</sup> Ω

<sup>−

1</sup> cm<sup>−

1</sup> at room temperature.

13. The AlN crystal of claim 10, wherein the AlN crystal is disposed within a semiconductor device.

14. The AlN crystal of claim 10, wherein a thickness thereof is at least approximately 0.1 mm and a diameter thereof is at least approximately 1 cm.

15. The AlN crystal of claim 14, wherein the diameter is at least approximately 2 cm.

16. The AlN crystal of claim 10, wherein dimensions thereof are at least 2 mm by 2 mm by 1 mm.

21. The AlN crystal of claim 10, further comprising an epitaxial layer disposed thereover.

22. The AlN crystal of claim 21, wherein the epitaxial layer comprises at least one of AlN, GaN, InN, or an alloy or mixture thereof.

23. The AlN crystal of claim 21, wherein the epitaxial layer comprises Al_xGa_1-xN.

24. The AlN crystal of claim 23, wherein x is greater than 0.5.