Claims
- 1. A method of producing a diamond substance of known acceptable quality by chemical vapor deposition, said known acceptable quality being indicated by the cathodoluminescence spectrum of a control diamond substance having said acceptable quality, which method comprises:
- a) providing a substrate in a chemical vapor deposition chamber;
- b) depositing a diamond substance on said substrate by chemical vapor deposition, said depositing comprising:
- i. introducing into said chamber a matrix gas comprising hydrogen and at least one additional gas selected from a hydrocarbon gas and carbon monoxide;
- ii. exciting said matrix gas to create a plasma while heating said substrate to a temperature of least 700.degree. C. to deposit a diamond substance on said substrate, said substance being crystallographically diamond;
- c) terminating said deposition at an early stage after commencing said deposition before a significant mass of said diamond substance has been deposited on said substrate, the amount of deposited diamond substance being sufficient to enable measurement of the luminescence spectrum of said diamond substance by cathodoluminescence measurement;
- d) removing said substrate bearing said diamond substance from said chamber;
- e) subjecting said diamond substance to a cathodoluminescence measurement to determine the luminescence spectrum of said diamond substance;
- f) comparing, utilizing the luminescence measurement of step (e), the luminescence spectrum of said diamond substance to the luminescence spectrum of said control diamond substance of said acceptable quality, the luminescence spectrum of said control diamond substance being indicative of a diamond substance of said acceptable quality whereby the comparison provides an indication of any deviation in said deposited diamond substance from said acceptable quality;
- g) returning said substance bearing said diamond substance, to said chemical vapor deposition chamber;
- h) depositing additional diamond substance on said substance by chemical vapor deposition according to step b);
- i) adjusting, based on the comparison of step f) , one or more of the pressure, substrate temperature, or matrix gas composition prevailing in step h) to compensate for deviation from acceptable quality indicated by the comparison of step f); and
- j) repeating steps c) through i) to produce a significant mass of said diamond substance of said acceptable quality.
- 2. The method of claim 1, wherein said matrix gas comprises a system of H.sub.2 and CH.sub.4 and an oxygen containing additive.
- 3. The method of 2, wherein said matrix gas comprises 100 volume parts by volume H.sub.2, 1 or more parts by volume CH.sub.4, said oxygen-containing additive comprises at least one of the group consisting of O.sub.2, CO.sub.2 and H.sub.2 O and the atomic ratio of oxygen to hydrogen in said matrix gas is greater than 2/100.
- 4. The method of claim 3, wherein said matrix gas comprises 1.5 or more parts by volume of O.sub.2 for every 100 parts by volume H.sub.2.
- 5. The method of claim 3, wherein said oxygen containing additive comprises 1 or more parts by volume of CO.sub.2 for every 100 parts by volume H.sub.2.
- 6. The method of claim 3, wherein said additive comprises 1 or more parts by volume H.sub.2 O for every 100 parts by volume H.sub.2.
- 7. The method of claim 3 , wherein said matrix gas further comprises a hydrogen containing additive selected from the group consisting of B.sub.2 H.sub.6, H.sub.2 S, PH.sub.3, AlH.sub.3, HCl, and H.sub.2 Se.
- 8. The method of claim 7, wherein said matrix gas comprises B.sub.2 H.sub.6 at a boron/carbon ratio not exceeding 1,000 ppm.
- 9. The method of claim 1, wherein said matrix gas comprises 15 or less parts by volume CO for every 100 parts by volume of H.sub.2.
- 10. The method of claim 1, wherein said matrix gas comprises H.sub.2, CO and an oxygen containing additive.
- 11. The method of claim 10, wherein said matrix gas comprises 15 or more parts by volume CO for every 100 parts by volume H.sub.2, said additive comprises at least one of the group selected from O.sub.2, CO.sub.2, and H.sub.2 O, and the atomic ratio of oxygen to hydrogen in said matrix gas is greater than 5/100.
- 12. The method of claim 11, wherein said oxygen-containing additive comprises 3 or more parts by volume O.sub.2 for every 100 parts by volume H.sub.2.
- 13. The method of claim 11, wherein said additive comprises 5 or more parts by volume of CO.sub.2 for every 100 parts by volume H.sub.2.
- 14. The method of claim 11, wherein said oxygen-containing additive comprises 5 or more parts by volume of H.sub.2 O for every 100 parts by volume H.sub.2.
- 15. The method of claim 1, wherein said matrix gas comprises H.sub.2 and CO and a hydrogen containing additive selected from the group consisting of B.sub.2 H.sub.6, H.sub.2 S, PH.sub.3, AlH.sub.3, HCl, AsH.sub.3, H.sub.2 Se.
- 16. The method of claim 7, wherein said matrix gas comprises B.sub.2 H.sub.6 at a boron/carbon ratio not exceeding 1,000 ppm.
- 17. The method of claim 1, wherein said matrix gas is excited by microwave or RF wave radiation.
- 18. The method of claim 1, wherein said substrate is heated to a temperature between about 700.degree. C. and 950.degree. C.
- 19. A method according to claim 1, wherein step e) comprises determining the peak luminescence value and the luminescence spectrum width at two lower luminescence values of the luminescence spectrum of said diamond substance, and wherein step f) comprises comparing said determined luminescence values with, respectively, the peak luminescence value and the luminescence spectrum width at said two lower luminescence values of the luminescence spectrum of said control diamond substance.
- 20. A method according to claim 19 wherein the higher of said lower luminescence values comprise a half-peak luminescence value.
- 21. A method according to claim 19 wherein said two lower luminescence values comprise a half-peak luminescence value and a of peak luminescence value.
- 22. A method according to claim 1 wherein said temperature in step b) ii) is not more than about 900.degree. C.
- 23. A method according to claim 1 wherein said temperature in step b) ii) is from 800.degree. C. to 900.degree. C.
- 24. A method according to claim 21 wherein the luminescence spectrum of said control diamond substance has:
- a peak value at a photron energy level of about 2.8 ev;
- a half-peak width of about 0.5 ev; and
- a 20% of peak width of about 0.8 ev.
- 25. A method according to claim 21 wherein the luminescence spectrum of said control diamond substance has:
- a peak value at a photron energy level of between about 2.4 and 2.5 ev;
- a half-peak width of about 0.9 ev; and
- a 20% of peak width of about 1.2 ev.
- 26. A method according to claim 1 wherein step i) comprises adjusting said matrix gas composition.
- 27. A method according to claim 1 wherein step i) comprises adjusting said pressure.
- 28. A method according to claim 1 wherein step i) comprises adjusting said substrate temperature.
Priority Claims (2)
Number |
Date |
Country |
Kind |
1-67228 |
Mar 1989 |
JPX |
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1-83378 |
Mar 1989 |
JPX |
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Parent Case Info
This application is a continuation, of application Ser. No. 07/494,750, filed Mar. 16, 1990, now abandoned.
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Continuations (1)
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Number |
Date |
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Parent |
494750 |
Mar 1990 |
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