Claims
- 1. A process for forming a substantially pure layer of an implantable element in a substrate which comprises:
- (a) selecting an implantable element and a substrate material to be implanted which, at the temperature to be used for the implantation:
- (i) have limited mutual solubility in one another; and
- (ii) do not form intermediate phases with one another; and
- (b) implanting a sufficient amount of the implantable element to form said desired substantially pure layer of the implantable element in the substrate material.
- 2. The process of claim 1 wherein said implanted substrate is annealed at a temperature not exceeding about 10.degree. C. below the melting point of the substrate to form said substantially pure layer.
- 3. The process of claim 2 wherein said implanted substrate is annealed at a temperature which ranges from at least about 20.degree. C. up to about 10.degree. C. below the melting point of the substrate to form said substantially pure layer.
- 4. The process of claim 1 wherein at least about 5.times.10.sup.16 atoms/cm.sup.2 of said implantable element are implanted in said substrate material to form said substantially pure layer therein.
- 5. The process of claim 2 wherein at least about 5.times.10.sup.17 atoms/cm.sup.2 of said implantable element are implanted in said substrate material to form said substantially pure layer therein.
- 6. The process of claim 1 wherein the solubility of said implantable element in said substrate material is less than about 10 at. %.
- 7. The process of claim 1 wherein the solubility of said implantable element in said substrate material is less than about 5 at. %.
- 8. The process of claim 1 wherein the solubility of said substrate material in said implantable element is less than about 10 at. %.
- 9. The process of claim 1 wherein he solubility of said substrate material in said implantable element is less than about 5 at. %.
- 10. The process of claim 1 wherein said implantation step is carried out at a temperature ranging from about -196.degree. C. to about 10.degree. C. below the melting point of the substrate.
- 11. The process of claim 1 wherein said implantation step is carried out at a temperature within the implantation temperature range to permit formation of said substantially pure layer of said implantable element without a post-implant annealing step.
- 12. The process of claim 1 wherein said implantable element is implanted into said substrate at an energy ranging from about 5 keV to about 2000 keV
- 13. The process of claim 1 wherein said implantation is carried out in the presence of a gas capable of reducing sputtering of said substrate materials during the implantation process.
- 14. The process of claim 13 wherein said gas capable of inhibiting sputtering during said implantation process is selected from the class consisting of oxygen, water vapor, carbon dioxide, and nitrogen.
- 15. The process of claim 1 including the further step of providing a coating on said substrate which will inhibit sputtering during said implantation process.
- 16. The process of claim 1 including the further step of exposing said substantially pure implanted layer after said implantation step by removing the surface layer of said substrate to expose said implanted layer.
- 17. The process of claim 16 wherein said step of removing a portion of said substrate to expose said implanted layer is carried out by sputtering, wet etching, dry etching, or by mechanical means.
- 18. The process of claim 1 wherein said implantation step comprises forming a shallow implant of said implantable element to form said substantially pure implanted layer so as to be exposed adjacent to the surface of said substrate.
- 19. The process of claim 1 wherein said implantation step is carried out two or more times at different energies to thereby form two or more of said substantially pure layers in said substrate.
- 20. The process of claim 19 wherein said two or more implantation steps are carried out using the same implantable element to form two or more layers of the same implanted element in said substrate.
- 21. The process of claim 19 wherein said two or more implantation steps are carried out using different implantable elements to form two or more layers of different implanted elements in said substrate.
- 22. The process of claim 1 wherein said step of forming said substantially pure layer in said substrate further includes forming a patterned buried layer in said substrate.
- 23. The process of claim 22 wherein said patterned layer in said substrate is formed by the step of masking said substrate prior to said implantation step.
- 24. The process of claim 22 wherein said patterned layer is formed in said substrate by using a focused ion beam to implant a pattern layer in said substrate.
- 25. A process for implanting a substantially pure layer of an implantable element in a substrate which comprises:
- (a) selecting an implantable element and a substrate to be implanted wherein, at the temperature to be used for the implantation:
- (i) the solubilities of said implantable element and said substrate material in one another are less than 10 at. % ; and
- (ii) no intermediate phases containing both said implantable element and said substrate material exist; and
- (b) implanting, at a temperature ranging from about -196.degree.C. to about 10.degree. C. below the melting point of the substrate, at least about 5.times.10.sup.16 atoms/cm.sup.2 of said implantable element in said substrate;
- to form said layer of said implantable element having a purity of at least about 90 at. % in said substrate.
- 26. A process for forming a substantially pure layer of an implantable element in a substrate which comprises:
- (a) selecting an implantable element and a substrate to be implanted wherein, at the temperature to be used for the implantation and annealing:
- (i) the solubilities of said implantable element and said substrate material in one another are less than 10 at. % ; and
- (ii) no intermediate phases containing both said implantable element and said substrate material exist;
- (b) implanting, at a temperature ranging from about -196.degree. C. to about 10.degree. C. below the melting point of the substrate, at least about 5.times.10.sup.16 atoms/cm.sup.2 of said implantable element in said substrate; and
- (c) annealing said implanted substrate at a temperature ranging from about 20.degree. C. to about 10.degree. C. below the melting point of the substrate for a period of about 1 second to about 100 hours;
- to form said layer of said implantable element having a purity of at least about 90 at. % in said substrate
- 27. A process for producing a substantially pure layer of aluminum in a beryllium substrate which comprises:
- (a) implanting aluminum ions into a beryllium substrate at an energy of about 200 keV and a fluence of at least about 1.1.times.10.sup.18 atoms/cm.sup.2 while maintaining the temperature below about 150.degree. C.; and
- (b) annealing said implanted beryllium substrate at a temperature of from about 400.degree. C. to just below 570.degree. C. for a period of from about 0.2 to 4 hours;
- to form said layer of substantially pure aluminum in said beryllium substrate
BACKGROUND OF THE INVENTION
The invention described herein arose in the course of, or under, Contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California.
US Referenced Citations (9)
Non-Patent Literature Citations (2)
Entry |
Buene et al., "Metastable Alloys of Be Prepared by Ion Implantation", Meturgical Transactions A, vol. 15A, Oct. '84 pp. 1787-1805. |
Myers et al., "Phase Equilibria & Diffusion in Be-Al-Fe System Using High Energy Ion Beams", Metallurgical Transactions A, vol. 7A, Jun. 76, pp. 795-802. |