Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-05T13:32:13.952Z Has data issue: false hasContentIssue false

The Effects of Sapphire Surface Treatments and Nitridation on GaN Nucleation Grown using Hydride Vapor Phase Epitaxy

Published online by Cambridge University Press:  01 February 2011

F. Dwikusuma
Affiliation:
Department of Chemical Engineering, University of Wisconsin, Madison, WI 53706
T. F. Kuech
Affiliation:
Department of Chemical Engineering, University of Wisconsin, Madison, WI 53706
Get access

Abstract

We have studied the effects of sapphire surface treatments and nitridation on GaN nucleation grown using the hydride vapor phase epitaxy technique. The surface treatments used were airannealing at 1400°C, etching in pure H2SO4 at 250°C, and etching in a 3:1 mixture of H2SO4:H3PO4 solution at 250°C. A nitridation step was carried out using 20% NH3 in N2 gas mixture at 1100°C. GaN nucleation and the early stage s of growth was investigated by short time growth and quench experiments. Atomic force microscopy and double crystal x-ray diffraction were used to examine the sapphire surface morphology, GaN island density, and GaN island structure. A lower density of GaN islands was grown on the air-annealed sapphire compared to the H2SO4-etched and 3:1 H2SO4:H3PO4-etched sapphire. GaN islands grown on the 3:1 H2SO4:H3PO4-etched sapphire had a broad mosaic spread due to preferential growth on surface pits. Sapphire nitridation resulted in a higher GaN island density with a smaller mosaic spread. A high density and uniform nucleation of GaN islands is critical in producing high quality thick GaN films. The H2SO4-etched sapphire and nitridation resulted in a high density of uniform GaN islands.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Wu, X. H., Kapolnek, D., Tarsa, E. J., Heying, B., Keller, S., Keller, B. P., Mishra, U. K., Denbaars, S. P., and Speck, J. S., Appl. Phys. Lett. 68, 1371 (1996).Google Scholar
2. Gu, S., Zhang, R., Shi, Y., Zheng, Y., Zhang, L., Dwikusuma, F., and Kuech, T. F., J. Cryst. Growth 231, 342 (2001).Google Scholar
3. Dwikusuma, F., Saulys, D., and Kuech, T. F., J. Electrochem. Soc. 149, G603 (2002).Google Scholar
4. Dwikusuma, F. and Kuech, T. F., submitted to J. Appl. Phys. March 2003.Google Scholar
5. Grandjean, N., Massies, J., and Leroux, M., Appl. Phys. Lett. 69, 2071, 1996.Google Scholar
6. Grandjean, N., Massies, J., Martinez, Y., Vennéguès, P., Leroux, M., and Laügt, M., J. Cryst. Growth 178, 220 (1997).Google Scholar
7. Fang, Z. Q., Look, D. C., Jasinski, J., Benamara, M., Liliental-Weber, Z., and Molnar, R. J., Appl. Phys. Lett. 78, 332 (2001).Google Scholar
8. Wu, X. H., Fini, P., Tarsa, E. J., Heying, B., Keller, S., Mishra, U. K., DenBaars, S. P., and Speck, J. S., J. Cryst. Growth 189/190, 2, 31 (1998).Google Scholar