Claims
- 1. A process for treating an as-grown chemical vapor deposited (CVD) polycrystalline starting diamond film with a thickness of greater than 200 um and having residual starting stresses and containing voids, comprising the step of subjecting said diamond film to a temperature of above about 1000.degree. C. and a hydrostatic pressure of above about 3 kilobars, said temperature and hydrostatic pressure are in the graphite-stable region, wherein graphitization of said polycrystalline diamond film is prevented and said voids are substantially reduced in size.
- 2. A process for treating polycrystalline CVD diamond film according to claim 1 wherein said pressure is applied through a non-oxidizing medium, said medium being selected from the group consisting of a noble gas, hydrogen, a salt, an inert powder or any inert substance capable of supporting substantially hydrostatic pressure at said temperatures and pressures.
- 3. A process for treating polycrystalline CVD diamond film according to claim 1 wherein said time period for annealing is approximated by the formula:
- t(T)=1.27.times.10-26exp(127,328/T) minutes
- where T is the absolute temperature in degrees Kelvin.
- 4. A process for treating polycrystalline CVD diamond film according to claim 1 wherein the temperature is less than 1600 degrees Centigrade.
- 5. A process for treating polycrystalline CVD diamond film according to claim 4 wherein the temperature is greater than 1900 degrees Centigrade.
- 6. A process for treating polycrystalline CVD diamond film according to claim 1 comprising wherein said resulting annealed CVD diamond film has reduced stresses.
- 7. A process of treating polycrystalline CVD diamond film according to claim 6 wherein said polycrystalline diamond film comprises substantially transparent columns of diamond crystals having an orientation selected from the group consisting of the <110>, the <100> and the <111> directions perpendicular to a base.
- 8. A process for treating polycrystalline CVD diamond film according to claim 1 wherein said starting polycrystalline diamond film has diamond crystals and grain boundaries between diamond crystals and is optically transparent.
- 9. A process for treating polycrystalline CVD diamond film according to claim 1 wherein said starting diamond film comprises impurities or intentionally additives in amounts less than 4000 parts per million.
- 10. A process for treating polycrystalline CVD diamond film according to claim 1 wherein said starting diamond film comprises diamond having a grain size of crystals of less than about 200 microns.
- 11. A process for treating polycrystalline CVD diamond film according to claim 1 wherein said starting diamond film comprises impurities or intentionally additives in amounts less than less than 100 parts per million.
Parent Case Info
This is a continuation of of application Ser. No. 08/238,545 filed on May 5, 1994, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (2)
Number |
Date |
Country |
27 32 211 A1 |
Jul 1977 |
DEX |
63-226197 |
Sep 1988 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Graphitization of diamond at zero pressure and at a high pressure. By G. Davies and T. Evans J.J. Thomson Physical Laboratory, Berkshire, England Proc. R. Soc. Lond. A. 328 pp. 413-427 1972. |
Plastic Deformation and "Work-Hardening" of Diamond. by R. C. DeVries Mat. Res. Bull. vol. 10 No. 11 pp. 1193-1200, 1975. |
Continuations (1)
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Number |
Date |
Country |
Parent |
238545 |
May 1994 |
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