Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-02T22:49:07.318Z Has data issue: false hasContentIssue false
  • English
  • Français

Comparison of Ni/Au, Pd/Au, and Cr/Au Metallizations for Ohmic Contacts to p-GaN

Published online by Cambridge University Press:  10 February 2011

J. T. Trexler ,
S. J. Pearton ,
P. H. Holloway ,
M. G. Mier ,
K. R. Evans  and
R. F. Karlicek Jr.
J. T. Trexler
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611–6400.
S. J. Pearton
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611–6400.
P. H. Holloway
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611–6400.
M. G. Mier
Affiliation:
Solid State Electronics Directorate, Wright Laboratory, Wright-Patterson Air Force Base, OH 45433–7323.
K. R. Evans
Affiliation:
Solid State Electronics Directorate, Wright Laboratory, Wright-Patterson Air Force Base, OH 45433–7323.
R. F. Karlicek Jr.
Affiliation:
EMCORE Corporation, Somerset, NJ 08873.
Get access

Abstract

Reactions between electron beam evaporated thin films of Ni/Au, Pd/Au, and Cr/Au on p-GaN with a carrier concentration of 9.8 × 1016 cm−3 were investigated in terms of their structural and electronic properties both as-deposited and following heat treatments up to 600°C (furnace anneals) and 900°C (RTA) in a flowing N2 ambient. Auger electron spectroscopy (AES) depth profiles were used to study the interfacial reactions between the contact metals and the p-GaN. The electrical properties were studied using room temperature current-voltage (1-V) measurements and the predominant conduction mechanisms in each contact scheme were determined from temperature dependent I-V measurements. The metallization schemes consisted of a 500 Å interfacial layer of Ni, Pd, or Cr followed by a 1000 Å capping layer of Au. All schemes were shown to be rectifying as-deposited with increased ohmic character upon heat treatment. The Cr/Au contacts became ohmic upon heating to 900°C for 15 seconds while the other schemes remained rectifying with lower breakdown voltages following heat treatment. The specific contact resistance of the Cr/Au contact was measured to be 4.3×10−1 Ωcm2. Both Ni and Cr have been shown to react with the underlying GaN above 400 °C while no evidence of a Pd:GaN reaction was seen. Pd forms a solid solution with the Au capping layer while both Ni and Cr tend to diffuse through the capping layer to the surface. All contacts were shown to have a combination of thermionic emission and thermionic field emission as their dominant conduction mechanism, depending on the magnitude of the applied reverse bias.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 449: Symposium N – III-V Nitrides , 1996 , 1091
Copyright
Copyright © Materials Research Society 1997

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 Maruska, H.P. and Tietjen, J.J., Appl. Phys. Lett. 15, 327 (1969).Google Scholar
2 Pankove, J., J. of Lumin. 7, 114 (1973).Google Scholar
3 Jenkins, D.W. and Dow, J.D., Phys. Rev. B 39, 3317, (1989).Google Scholar
4 Sze, S.M., Physics of Semiconductor Devices. 2nd ed. (John Wiley + Sons, Inc. Publishers, New York, 1981) p. 304.Google Scholar
5 Wagner, C., Phys. A. 32, 641 (1931).Google Scholar
6 Schottky, W. and Spence, E., Wiss. Veroff. Siemens-Werken, 18, 225 (1939)Google Scholar
7 Padovani, F. and Stratton, R., Solid St. Electron., 9, 695 (1966).Google Scholar
8 Lin, M.E., Ma, Z., Huang, F.Y. and Morkoc, H., Appl. Phys. Lett. 64, 2557 (1994).Google Scholar
9 Nakamura, S., Mukai, T., and Senoh, M., Jpn. J. Appl. Phys. 30, L1998 (1991).Google Scholar
10 Nakamura, S., Senoh, M., and Mukai, T., Jpn. J. Appl. Phys. 32, L8 (1993).Google Scholar
11 Nakamura, S., Senoh, M., and Mukai, T., Appl. Phys. Lett. 62, 2390 (1993).Google Scholar
12 Nakamura, S., Mukai, T., Senoh, M., Appl. Phys. Lett. 64, 2557 (1994).Google Scholar
13 Nakamura, S., Senoh, M., Nagahama, S., lwasa, N., Yamada, T., Matsushita, T., Kiyoku, H. and Sugimoto, Y., Jpn. J. Appl. Phys. 35, L74 (1996).Google Scholar
14 Sze, S.M., Physics of Semiconductor Devices. 2nd ed. (John Wiley + Sons Inc. Publishers, New York, 1981) p. 251.Google Scholar
15 Bermudez, V. M., Kaplan, R., Khan, M.A. and Kuznia, J.N., Phys. Rev. B. 48, 2436 (1993).Google Scholar
16 Mohney, S.E., Luther, B.P. and Jackson, T.N., Mat. Res. Soc. Proc. 395, 843 (1996).Google Scholar