Method of forming an optically-finished thin diamond film, diamond substrate, or diamond window of high aspect ratio

Patent metadata

Field	Value
Publication number	US-10494713-B2
Application number	US-201615093160-A
Country	US
Kind code	B2
Filing date	Apr 7, 2016
Priority date	Apr 16, 2015
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

In a method of forming a diamond film, diamond substrate, or diamond window, a silicon substrate is provided and the diamond film, diamond substrate, or diamond window is CVD grown on a surface of the silicon substrate. The grown diamond film, diamond substrate, or diamond window has an aspect ratio ≥100, wherein the aspect ratio is a ratio of a largest dimension of the diamond film, diamond substrate, or diamond window divided by a thickness of the diamond film, diamond substrate, or diamond window. The silicon substrate has a thickness greater than or equal to 2 mm. The silicon substrate can optionally be removed or separated from the grown diamond film, diamond substrate, or diamond window.

First claim

The invention claimed is:

1. A method of forming a planar, free-standing diamond film, diamond substrate, or diamond window comprising:
(a) CVD growing on a surface of a silicon substrate a diamond film, diamond substrate, or diamond window having an aspect ratio ≥100 and a thickness between 150-999 microns, wherein the aspect ratio is a ratio of a largest dimension of the diamond film, diamond substrate, or diamond window divided by a thickness of the diamond film, diamond substrate, or diamond window; and
(b) chemically or mechanically removing the silicon substrate from the grown diamond film, diamond substrate, or diamond window.

2. The method of claim 1 , wherein the silicon substrate has a thickness ≥2 mm.

3. The method of claim 1 , further including, prior to step (a), polishing the surface of the silicon substrate to an optical finish having a surface roughness (Ra)≤20 nm.

4. The method of claim 3 , wherein:
a nucleation side of the as-grown diamond film, diamond substrate, or diamond window has an Ra greater than the Ra of the polished surface of the silicon substrate; and
for an Ra of the polished the surface of the silicon substrate ≤20 nm, the Ra of the nucleation side of the as-grown diamond film, diamond substrate, or diamond window is ≤50 nm.

5. The method of claim 3 , wherein:
a nucleation side of the as-grown diamond film, diamond substrate, or diamond window has an Ra greater than the Ra of the polished surface of the silicon substrate; and
for an Ra of the polished the surface of the silicon substrate ≤15 nm, the Ra of the nucleation side of the as-grown diamond film, diamond substrate, or diamond window is ≤30 nm.

6. The method of claim 3 , wherein:
a nucleation side of the as-grown diamond film, diamond substrate, or diamond window has an Ra greater than the Ra of the polished surface of the silicon substrate; and
for an Ra of the polished the surface of the silicon substrate ≤2 nm, the Ra of the nucleation side of the as-grown diamond film, diamond substrate, or diamond window is ≤10 nm.

7. The method of claim 1 , wherein the surface of the silicon substrate and a nucleation side of the as-grown diamond film, diamond substrate, or diamond window each have a surface roughness (Ra)≥750 nm.

8. The method of claim 1 , further including, while the diamond film, diamond substrate, or diamond window is still on the silicon substrate, polishing a growth surface of the diamond film, diamond substrate, or diamond window to a surface roughness (Ra)≤50 nm.

9. The method of claim 1 , wherein:
a shape of the nucleation side of the as-grown diamond film, diamond substrate, or diamond window is a conformal negative of the shape of the surface of the silicon substrate.

10. The method of claim 1 , wherein a growth side of the as-grown diamond film, diamond substrate, or diamond window has a greater thermal conductivity than the nucleation side of the as-grown diamond film, diamond substrate, or diamond window.

11. The method of claim 1 , further including at least one of the following:
applying a light management coating to a growth surface of the grown diamond film, diamond substrate, or diamond window; and
after removing the silicon substrate from the grown diamond film, diamond substrate, or diamond window, applying the light management coating to a nucleation side of the grown diamond film, diamond substrate, or diamond window.

12. The method of claim 1 , further including cutting the silicon substrate having the diamond film, diamond substrate, or diamond window grown thereon into one or more pieces.

13. The method of claim 1 , wherein step (a) includes CVD growing the diamond film, diamond substrate, or diamond window in an atmosphere that includes at least one of the following: oxygen, carbon monoxide, carbon dioxide, nitrogen, and boron.

14. The method of claim 1 , wherein, prior to step (a), the surface of the silicon substrate is seeded with diamond particles.

15. The method of claim 14 , wherein the silicon substrate is seeded with diamond particles via at least one of the following processes: (1) ultrasonic treatment of the silicon substrate in a ultrasonic bath comprised of a submicron or micron-sized diamond powder in a liquid suspension solution; and (2) ultrasonic treatment of the silicon substrate in a ultrasonic bath comprised of nano-crystal diamond powder having an average particle size <100 nm in a liquid suspension solution.

16. The method of claim 15 , wherein the liquid suspension solution comprises one or more of the following: water, alcohol, hydrocarbon, and organic solvent.

17. The method of claim 14 , wherein the silicon substrate is seeded with diamond particles via a least one of the following processes: (1) ultrasonic treatment of the silicon substrate in a bath of aqueous diamond slurries or organic diamond slurries, or (2) rubbing the silicon substrate with diamond powders.

18. The method of claim 1 , wherein the largest dimension of the silicon substrate is ≥30 mm.

19. The method of claim 18 , wherein the largest dimension of the silicon substrate is a diameter of the silicon substrate.

20. The method of claim 1 , wherein the silicon substrate has a thickness ≥8 mm.

21. The method of claim 1 , further including, prior to step (a), polishing the surface of the silicon substrate to an optical finish having a surface roughness (Ra)≤2 nm.

22. The method of claim 1 , further including, while the diamond film, diamond substrate, or diamond window is still on the silicon substrate, polishing a growth surface of the diamond film, diamond substrate, or diamond window to a surface roughness (Ra)≤10 nm.

23. The method of claim 1 , wherein the largest dimension of the silicon substrate is ≥50.8 mm.

24. The method of claim 1 , wherein the largest dimension of the silicon substrate is ≥127 mm.

25. A method of forming a planar, free-standing diamond film, diamond substrate, or diamond window comprising:
(a) CVD growing on a surface of a silicon substrate polished to an optical finish having a surface roughness (Ra)≤20 nm a diamond film, diamond substrate, or diamond window having an aspect ratio ≥100 and a thickness between 150-999 microns, wherein the aspect ratio is a ratio of a largest dimension of the diamond film, diamond substrate, or diamond window divided by a thickness of the diamond film, diamond substrate, or diamond window; and
(b) chemically or mechanically removing the silicon substrate from the grown diamond film, diamond substrate, or diamond window.

26. A method of forming a planar, free-standing diamond film, diamond substrate, or diamond window comprising:
(a) CVD growing on a surface of a silicon substrate a diamond film, diamond substrate, or diamond window having an aspect ratio ≥100 and a thickness between 150-999 microns, wherein the aspect ratio is a ratio of a largest dimension of the diamond film, diamond substrate, or diamond window divided by a thickness of the diamond film, diamond substrate, or diamond window, wherein the surface is seeded with diamond particles via ultrasonic treatment of the silicon substrate in a ultrasonic bath comprised of (1) submicron or micron-sized diamond powder in a liquid suspension solution; or (2) nano-crystal diamond powder having an average particle size <100 nm in a liquid suspension solution; and
(b) chemically or mechanically removing the silicon substrate from the grown diamond film, diamond subs

Assignees

• Ii Vi Inc

Inventors

• Xu Wen-Qing
• Anderson Thomas E
• Barbarossa Giovanni
• Eissler Elgin E
• Liu Chao
• Tanner Charles D

Classifications

• C23C16/01

  on temporary substrates, e.g. substrates subsequently removed by etching · CPC title

• C23C16/56

  After-treatment · CPC title

• C23C16/274 Primary

  using microwave discharges · CPC title

• C23C16/511

  using microwave discharges · CPC title

• C23C16/02

  Pretreatment of the material to be coated (C23C16/04 takes precedence) · CPC title