Skip to main content Accessibility help
×
Home

Evidence from EELS of Oxygen in the Nucleation Layer of a MBE grown III-N HEMT

  • Tyler J. Eustis (a1), John Silcox (a2), Michael J. Murphy (a3) and William J. Schaff (a3)

Abstract

The presence of oxygen throughout the nominally AlN nucleation layer of a RF assisted MBE grown III-N HEMT was revealed upon examination by Electron Energy Loss Spectroscopy (EELS) in a Scanning Transmission Electron Microscope (STEM). The nucleation layer generates the correct polarity (gallium face) required for producing a piezoelectric induced high mobility two dimensional electron gas at the AlGaN/GaN heterojunction. Only AlN or AlGaN nucleation layers have provided gallium face polarity in RF assisted MBE grown III-N's on sapphire. The sample was grown at Cornell University in a Varian GenII MBE using an EPI Uni-Bulb nitrogen plasma source. The nucleation layer was examined in the Cornell University STEM using Annular Dark Field (ADF) imaging and Parallel Electron Energy Loss Spectroscopy (PEELS). Bright Field TEM reveals a relatively crystallographically sharp interface, while the PEELS reveal a chemically diffuse interface. PEELS of the nitrogen and oxygen K-edges at approximately 5-Angstrom steps across the GaN/AlN/sapphire interfaces reveals the presence of oxygen in the AlN nucleation layer. The gradient suggests that the oxygen has diffused into the nucleation region from the sapphire substrate forming this oxygen containing AlN layer. Based on energy loss near edge structure (ELNES), oxygen is in octahedral interstitial sites in the AlN and Al is both tetrahedrally and octahedrally coordinated in the oxygen rich region of the AlN.

Copyright

References

Hide All
1. Hangleiter, A., Seo, I. Jin, Kollmer, H., Heppel, S., Off, J., and Scholz, F., MRS Internet Journal of Nitride Semiconductor Research, 3 (15), (1998).
2. Asbeck, P. M., Yu, E. T., Lau, S. S., Sullivan, G. J., Hove, J. Van, and Redwing, J., Electronics Letters, 33, 1230–1, (1997).
3. Bernardini, F., Fiorentini, V., and Vanderbilt, D., Physical Review B, 56, R100247, (1997).
4. Bykhovski, A. D., Gelmont, B. L., and Shur, M. S., Journal of Applied Physics, 81, 6332–8, (1997).
5. Nardelli, M. B., Rapcewicz, K., and Bernholc, J., Applied Physics Letters, 71, 3135–7, (1997).
6. Takeuchi, T., Takeuchi, H., Sota, S., Sakai, H., Amano, H., and Akasaki, I., Japanese Journal of Applied Physics, Part 2, 36, L1779, (1997).
7. Yu, E. T., Sullivan, G. J., Asbeck, P. M., Wang, C. D., Qiao, D., and Lau, S. S., Applied Physics Letters, 71, 2794–6, (1997).
8. Murphy, M. J., Chu, K., Wu, H., Yeo, W., Schaff, W. J., Ambacher, O., Smart, J., Shearly, J. R., Eastman, L. F., and Eustis, T. J., Journal of Vacuum Science & Technology B, 17, 1252–4, (1999).
9. Benedict, J. P., Anderson, R. M., and Klepeis, S. J., in Proceedings of the Twenty-Eighth Annual Technical Meeting of the International Metallographics Society, Albuquerque, NM, USA, 1996 (ASM Int; Materials Park, OH, USA), p. 277–84.
10. Egerton, R. F., Electron Energy-Loss Spectroscopy in the Electron Microscope, 2nd ed. (Plenum Press, New York, 1996), p. 485.
11. Serin, V., Colliex, C., Brydson, R., Matar, S., and Boucher, F., Physical Review B, 58, 5106–15, (1998).
12. Ourmazd, A., Taylor, D. W., Cunningham, J., and Tu, C. W., Physical Review Letters, 62, 933–6, (1989).
13. Yeadon, M., Marshall, M. T., Hamdani, F., Pekin, S., Morkoc, H., and Gibson, J. M., Journal of Applied Physics, 83, 2847–50, (1998).
14. Abaidia, S., Serin, V., Zanchi, G., Kihn, Y., and Sevely, J., Philosophical Magazine A, 72, 1657–70, (1995).
15. Katsikini, M., Paloura, E. C., Cheng, T. S., and Foxon, C. T., Journal of Applied Physics, 82, 1166–71, (1997).
16. Mo, S. D. and Ching, W. Y., Physical Review B, 57, 15219–28, (1998).
17. Brydson, R., Journal of Physics D, 29, 1699–708, (1996).

Evidence from EELS of Oxygen in the Nucleation Layer of a MBE grown III-N HEMT

  • Tyler J. Eustis (a1), John Silcox (a2), Michael J. Murphy (a3) and William J. Schaff (a3)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed