Claims
- 1. A method for fabricating a gallium nitride-based layer having a desired resistivity atop a sapphire (0001) substrate, comprising:a) selecting a set of process conditions for growth at a first temperature and deposition rate of an aluminum nitride-based buffer layer on the sapphire substrate, followed by growth at a second temperature and deposition rate of a gallium nitride-based base layer upon said buffer layer; b) calculating the required thickness of said buffer layer based on said process conditions and said desired resistivity; c) depositing the buffer layer; and d) depositing the base layer.
- 2. The method of claim 1, wherein the base layer consists essentially of nominally undoped gallium nitride-based material.
- 3. The method of claim 1, wherein the buffer layer consists essentially of nominally undoped aluminum nitride-based material.
- 4. The method of claim 1, wherein said base layer consists essentially of gallium nitride.
- 5. The method of claim 1, wherein said buffer layer consists essentially of aluminum nitride.
- 6. The method of claim 1, wherein the buffer layer is deposited using an MOCVD technique.
- 7. The method of claim 1, wherein the base layer is deposited using an MOCVD technique.
- 8. The method of claim 1, wherein the buffer layer is deposited at temperatures between about 400° C. and 550° C.
- 9. The method of claim 1, wherein the base layer is deposited at temperatures between about 800° C. and 950° C.
- 10. The method of claim 1, wherein the buffer layer is deposited at a rate between 0.1 nanometers/second and 1.0 nanometers/second.
- 11. The method of claim 1, wherein said preselected resistivity is less than 0.1 Ω-cm.
- 12. The method of claim 1, wherein said preselected resistivity is between 0.1 Ω-cm and 1.0 Ω-cm.
- 13. The method of claim 1, wherein said preselected resistivity is between 1 Ω-cm and 100 Ω-cm.
- 14. The method of claim 1, wherein said preselected resistivity is greater than 100 Ω-cm.
- 15. The method of claim 1, wherein said preselected resistivity is greater than 106 Ω-cm.
- 16. A device fabricated using the process of claim 1.
Government Interests
This invention was made with Government support under Contract DE-AC04-94DP85000 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5290393 |
Nakamura |
Mar 1994 |
A |
Non-Patent Literature Citations (1)
Entry |
Ebel, R. et al., “Buffer layers for the growth of GaN on sapphire by molecular beam epitaxy”, J Crystal Growth pp. 433-436, May 1999. |