Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-10T20:18:41.819Z Has data issue: false hasContentIssue false
  • English
  • Français

Low Temperature Selected Area Re-Growth of Ohmic Contacts for III-N FETs

Published online by Cambridge University Press:  01 February 2011

Yoganand Saripalli ,
Chang Zeng ,
Yawei Jin ,
Joseph P Long ,
Judith A Grenko ,
Krishnanshu Dandu ,
Mark A.L Johnson  and
Doug W Barlage
Yoganand Saripalli
Affiliation:
ynsaripa@ncsu.edu, North Carolina State University, Materials Science and Engineering, 112 MRC,, 2410 Campus Shore Drive, Raleigh, NC, 27606, United States, 919-513-4460, 919-515-7724
Chang Zeng
Affiliation:
czeng@ncsu.edu
Yawei Jin
Affiliation:
yjin3@ncsu.edu
Joseph P Long
Affiliation:
jplong@ncsu.edu
Judith A Grenko
Affiliation:
jagrenko@ncsu.edu
Krishnanshu Dandu
Affiliation:
kdandu@ncsu.edu
Mark A.L Johnson
Affiliation:
mark_johnson@ncsu.edu
Doug W Barlage
Affiliation:
dwbarlag@ncsu.edu
Get access

Abstract

GaN has a wide band gap energy, high electron mobility, high saturation velocity, and excellent thermal properties making it a promising material for high power and high frequency electronic devices. The development of enhancement mode GaN metal oxide semiconductor (MOS) transistors has been elusive due to the non-availability of a good insulating gate dielectric and the difficulty in forming of ohmic source/drain regions. Ion-implantation of dopants causes severe lattice damage requiring a high temperature post-implant anneal and has not been a successful method to obtain acceptable low-resistance source/drain regions. At the same time, gate dielectrics for most compound semiconductors, in addition to difficulties in minimizing the density of interface states which pin the Fermi level by inducing trap levels in the midgap, are degraded by instabilities as a result of high temperature annealing. The paper presents the development ohmic source/drain contacts for GaN MOSFETs by selected area epitaxial regrowth. Re-growth of GaN on patterned substrates by metal-organic chemical vapor deposition (MOCVD) employs a growth regime to decrease the enhanced growth rates and island formation that result from the diffusion of precursors to the selected area. The enhanced growth rate is 4.5μm/hr compared to 0.5μm/hr of the as-grown GaN on the unpatterned substrate. The enhanced growth rate also results in heavily porous GaN. Selected area growth, device processing, the material and device characterization results will be presented. In particular the selected area growth of doped contacts in the 800°C temperature range leads to superior morphology and contact resistance as compared to similar contacts grown at 1060°C. The contact resistivity of the n+ re-growth region measured was ∼2×10-4 Ω-m and the morphology of the re-grown region was comparable to the as-grown GaN with an RMS roughness ∼1.4nm. The success of fabricating low temperature contacts for GaN enhancement mode MOS transistors is a critical step in fabricating these devices opening new applications.

Keywords

metalorganic depositionmorphologyreactive ion etching
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 892 , 2005 , 0892-FF16-01
Copyright
Copyright © Materials Research Society 2006

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

REFERENCES

1. Shur, M., Gaska, R., Khan, M.A., Materials Science Forum, 353–356, pp 807–814 (2001).CrossRefGoogle Scholar
2. Pearton, S.J., Ren, F.. Zhang, A.P., and Lee, K.P., Materials Science and Engineering R 30 p55–212 (2000).CrossRefGoogle Scholar
3. Hudgins, J., Simin, G.S., Khan, M.A., IEEE Proceedings, pp-1747–1752 (2002).Google Scholar
4. Yoder, M.N., IEEE Transactions on Electronic Devices, 43(10), pp1633–36 (1996).CrossRefGoogle Scholar
5. Lieber, C.M., MRS Bulletin, pp-486 (2003)CrossRefGoogle Scholar
6. Khan, M.A., Kuznia, J.N., Van Hove, J.M., Pan, N. and Carter, J., Appl. Phys. Lett, 60 (24), p 3027 (1992)CrossRefGoogle Scholar
7. Khan, M.A., Bhattarai, A., Kuznia, J.N., Olson, D.T., Appl. Phys. Lett, 63 (9), p1214 (1993).CrossRefGoogle Scholar
8. Matocha, K., Chow, T.P., Gutmann, R.J., IEEE Transactions on Electron Devices, 52 (1), p6 (2005)Google Scholar
9. Ren, F., Pearton, S.J., Abernathy, C.R., Baca, A., Cheng, P., Shul, R.J., Chu, S.N.G., Hong, M., Schurman, M.J., Lothian, J.R., Sol. St. Elec, 43, p 1817, (1999).CrossRefGoogle Scholar
10. Irokawa, Y., Nakano, Y., Ishiko, M., Kachi, T., Kim, J., Ren, F., Gila, B.P., Onstine, A.H., Abernathy, C.R., Pearton, S.J., Pan, C.C., Chen, G.T., Chyi, J.I., Appl. Phys. Lett, 84(15), p2919 (2004).CrossRefGoogle Scholar
11. Pearton, S.J., Ren, F., Adv. Mat., 12 (21), p1571 (2000).3.0.CO;2-T>CrossRef3.0.CO;2-T>Google Scholar
12. Heikman, S., Denbaars, S.P., Mishra, U.K., Jpn. J. Appl. Phys, 40, - 565 (2001).CrossRefGoogle Scholar
13. Kawai, H., Hara, M., Nakamura, F., Asatsuma, T., Koboyashi, T., Imanaga, S., J. Cryst. Growth, 189/190, p 738 (1998).CrossRefGoogle Scholar
14. Chen, C.H., Keller, S., Parish, G., Vetury, R., Kozodoy, P., Hu, E.L., Denbaars, S.P., Mishra, U.K., Wu, Y., Appl. Phys. Lett, 73 (21), p3147 (1998).Google Scholar
15. Saripalli, Y.N., Zeng, C., Long, J.P., Barlage, D.W., Johnson, M.A.L., and Braddock, D., J. Cryst. Growth, in press.Google Scholar
16. Adesida, I., Youtsey, C., Ping, A.T., Khan, F., Romano, L.T., and Bulman, G., MRS Internet J. Nitride Semiconductor Res. 5S1, G1.4 (1999).Google Scholar
17. Ohring, M., Materials Science of Thin Films, (Second Edition, Academic Press, 2002 New York), p 378–393.Google Scholar
18. Koleske, D., Wickenden, A.E., Henry, R.L., Desisto, W.J., Gorman, R.J., J. Appl. Phys, 84(4), p1998 (1998).CrossRefGoogle Scholar
19. He, L., Gu, X., Xie, J., Yun, F., Baski, A.A., Morkoc, H., MRS Symposium Proc. Vol 798, Y10.64.1, 2004.Google Scholar
20. Wang, D., Park, M., Saripalli, Y.N., Zeng, C., Long, J.P., Johnson, M.A.L., Barlage, D.W., Appl. Phys. Lett, (submitted).Google Scholar