Thermal control for formation and processing of aluminum nitride

Patent metadata

Field	Value
Publication number	US-11913136-B2
Application number	US-202318093428-A
Country	US
Kind code	B2
Filing date	Jan 5, 2023
Priority date	Nov 10, 2017
Publication date	Feb 27, 2024
Grant date	Feb 27, 2024

Abstract

In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.

First claim

What is claimed is:

1. A single-crystal AlN substrate having an ultraviolet (UV) transparency metric ranging from approximately 20 cm 3 to approximately 5000 cm 3 at a wavelength of interest of 265 nm, the UV transparency metric being defined in cm 3 as:

d

10
×
F
⁢

⁢
W
⁢

⁢
H
⁢

⁢
M
×

a
2

wherein d is a diameter of the AlN substrate in mm, FWHM is a full-width at half-maximum of an x-ray diffraction curve of the AlN substrate in radians, and a is an absorption coefficient of the AlN substrate at the wavelength of interest.

2. The AlN substrate of claim 1 , wherein the diameter of the AlN substrate is at least approximately 50 mm.

3. The AlN substrate of claim 1 , wherein a diameter of the AlN substrate is no greater than approximately 150 mm.

4. The AlN substrate of claim 1 , further comprising a light-emitting device disposed thereover, the light-emitting device (i) comprising a light-emitting diode or a laser, and (ii) being configured to emit ultraviolet light.

5. The AlN substrate of claim 1 , wherein (i) a density of threading edge dislocations in the AlN substrate is less than 5×10 3 cm −2 , and (ii) a density of threading screw dislocations in the AlN substrate is less than 10 cm −2 .

6. The AlN substrate of claim 1 , wherein (i) a silicon concentration of the AlN substrate is less than 1×10 17 cm −3 , (ii) an oxygen concentration of the AlN substrate is less than 1×10 17 cm −3 , and (iii) a carbon concentration of the AlN substrate is less than 3×10 17 cm −3 .

7. The AlN substrate of claim 1 , wherein a thickness of the substrate is 100 μm or greater.

8. The AlN substrate of claim 1 , further comprising an epitaxial semiconductor layer disposed thereover.

9. A single-crystalline AlN boule having a length of approximately 15 mm or larger, wherein a diameter of at least a portion of the AlN boule is approximately 50 mm or larger, and wherein:
an ultraviolet (UV) absorption coefficient of the AlN boule is less than 60 cm −1 for a wavelength range of approximately 220 nm to approximately 480 nm;
an oxygen concentration of the AlN boule is less than 4×10 17 cm −3 ;
a carbon concentration of the AlN boule is less than 4×10 17 cm −3 ; and
a ratio of the carbon concentration of the AlN boule to the oxygen concentration of the AlN boule is less than 1.0.

10. The AlN boule of claim 9 , wherein the UV absorption coefficient is less than 30 cm −1 for the wavelength range of approximately 220 nm to approximately 480 nm.

11. The AlN boule of claim 9 , wherein (i) the oxygen concentration of the AlN boule is less than 1×10 17 cm −3 , and (ii) the carbon concentration of the AlN boule is less than 3×10 17 cm −3 .

12. The AlN boule of claim 9 , wherein the ratio of the carbon concentration of the AlN boule to the oxygen concentration of the AlN boule is less than 0.5.

13. The AlN boule of claim 9 , wherein the length of the boule is selected from the range of approximately 20 mm to approximately 35 mm.

14. The AlN boule of claim 9 , wherein (i) a density of threading edge dislocations in the AlN boule is less than 5×10 3 cm −2 , and (ii) a density of threading screw dislocations in the AlN boule is less than 10 cm −2 .

15. The AlN boule of claim 9 , wherein a silicon concentration of the AlN boule is less than 1×10 17 cm −3 .

16. The AlN boule of claim 9 , wherein the UV absorption coefficient of the AlN boule is less than 10 cm −1 for a wavelength range of approximately 350 nm to approximately 480 nm.

17. A single-crystalline AlN substrate having a diameter of approximately 50 mm or larger, and wherein:
an ultraviolet (UV) absorption coefficient of the AlN substrate is less than 60 cm −1 for a wavelength range of approximately 220 nm to approximately 480 nm;
an oxygen concentration of the AlN substrate is less than 4×10 17 cm −3 ;
a carbon concentration of the AlN substrate is less than 4×10 17 cm −3 ; and
a ratio of the carbon concentration of the AlN substrate to the oxygen concentration of the AlN substrate is less than 1.0.

18. The AlN substrate of claim 17 , wherein a thickness of the substrate is 100 μm or greater.

19. The AlN substrate of claim 17 , further comprising an epitaxial semiconductor layer disposed thereover.

20. The AlN substrate of claim 17 , wherein the UV absorption coefficient is less than 30 cm −1 for the wavelength range of approximately 220 nm to approximately 480 nm.

21. The AlN substrate of claim 17 , wherein the UV absorption coefficient is less than 10 cm −1 for a wavelength range of approximately 350 nm to approximately 480 nm.

22. The AlN substrate of claim 17 , wherein (i) the oxygen concentration of the AlN substrate is less than 1×10 17 cm −3 , and (ii) the carbon concentration of the AlN substrate is less than 3×10 17 cm −3 .

23. The AlN substrate of claim 17 , wherein the ratio of the carbon concentration of the AlN substrate to the oxygen concentration of the AlN substrate is less than 0.5.

24. The AlN substrate of claim 17 , wherein (i) a density of threading edge dislocations in the AlN substrate is less than 5×10 3 cm −2 , and (ii) a density of threading screw dislocations in the AlN substrate is less than 10 cm −2 .

25. The AlN substrate of claim 17 , wherein a silicon concentration of the AlN substrate is less than 1×10 17 cm −3 .

26. The AlN substrate of claim 17 , wherein the diameter of the AlN substrate is no greater than approximately 150 mm.

27. The AlN substrate of claim 17 , further comprising a light-emitting device disposed thereover, the light-emitting device (i) comprising a light-emitting diode or a laser, and (ii) being configured to emit ultraviolet light.

28. The AlN substrate of claim 17 , wherein a thermal conductivity of the AlN substrate is approximately 290 W/m·K or greater at room temperature.

29. The AlN substrate of claim 17 , wherein a crystalline orientation of the AlN substrate is substantially parallel to a c-axis.

30. The AlN substrate of claim 17 , wherein a crystalline orientation of the AlN substrate is angled at least approximately 10° relative to a c-axis.

31. The AlN substrate of claim 1 , wherein an ultraviolet (UV) absorption coefficient of the AlN substrate is less than 60 cm −1 for a wavelength range of approximately 220 nm to approximately 480 nm.

32. The AlN substrate of claim 1 , wherein an ultraviolet (UV) absorption coefficient of the AlN substrate is less than 30 cm −1 for a wavelength range of approximately 220 nm to approximately 480 nm.

33. The AlN substrate of claim 1 , wherein an ultraviolet (UV) absorption coefficient of the AlN substrate is less than 10 cm −1 for a wavelength range of approximately 220 nm to approximately 480 nm.

Assignees

• Bondokov Robert T
• Chen Jianfeng
• Yamaoka Keisuke
• Wang Shichao
• Rao Shailaja P
• Suzuki Takashi
• Schowalter Leo J
• Crystal Is Inc

Inventors

• Bondokov Robert T
• Chen Jianfeng
• Yamaoka Keisuke
• Wang Shichao
• Rao Shailaja P
• Suzuki Takashi
• Schowalter Leo J

Classifications

• H10P14/2908

  Nitrides · CPC title

• H10H20/0137 Primary

  the light-emitting regions comprising nitride materials · CPC title

• C30B29/403 Primary

  AIII-nitrides · CPC title

• C01B21/072

  with aluminium · CPC title

• C30B23/002

  Controlling or regulating · CPC title