Hostname: page-component-848d4c4894-xfwgj Total loading time: 0 Render date: 2024-06-19T16:30:27.537Z Has data issue: false hasContentIssue false

Ohmic Contact Formation to Doped GaN

Published online by Cambridge University Press:  21 February 2011

L. L. Smith
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907
M. D. Bremser
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907
E. P. Carlson
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907
T. W. Weeks Jr.
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907
Y. Huang
Affiliation:
Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704
M. J. Kim
Affiliation:
Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704
R.W. Carpenter
Affiliation:
Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704
R. F. Davis
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907
Get access

Abstract

Ohmic contact strategies for n- and p-type GaN have been investigated electrically, chemically, and microstructurally using transmission line measurements, high-resolution EELS and cross-sectional TEM, respectively. The contributions to contact performance from work function differences, carrier concentrations, annealing treatments, and interface metallurgy have been examined. The contact materials of Ti, TiN, Au, and Au/Mg were deposited via electron beam evaporation; Al was deposited via thermal evaporation. As-deposited Al and TiN contacts to highly doped n-GaN were ohmic, with room-temperature specific contact resistivities of 8.6×10−5 Ω cm2 and 2.5×10−5 Ωcm2 respectively. The Ti contacts developed low-resistivity ohmic behavior as a result of annealing; TiN contacts also improved with further heat treatment. For p-GaN, Au became ohmic with annealing, while Au/Mg contacts were ohmic in the as-deposited condition. The performance, structure, and composition of different contact schemes varied widely from system to system. An integrated analysis of the results of this study is presented below and coupled with a discussion of the most appropriate contact systems for both n- and p-type GaN.

Type
Research Article
Copyright
Copyright © Materials Research Society 1996

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 Rideout, V.L., Solid-St. Electron. 18 541 (1975).Google Scholar
2 Williams, R., Modern GaAs Processing Techniques (Artech House, Norwood, MA, 1990) pp. 211227.Google Scholar
3 Shen, T. C., Gao, G. B., Morkoç, H., J. Vac. Sci. Technol. B 10 (5) 2113 (1992).Google Scholar
4 Marshall, E.D. and Murakami, M., in Contacts to Semiconductors, edited by Brillson, L.J. (Noyes, Park Ridge, NJ, 1993) pp. 166.Google Scholar
5 Henisch, H.K., Semiconductor Contacts. (Clarendon Press, Oxford, 1984) pp. 4371.Google Scholar
6 Rhoderick, E.H. and Williams, R.H., Metal-Semiconductor Contacts. 2nd ed. (Oxford University Press, New York, 1988), pp. 1117.Google Scholar
7 Kurtin, S., McGill, T.C. and Mead, C.A., Phys. Rev. Lett. 22 (26) 1433 (1969).Google Scholar
8 Smith, L.L. and Davis, R.F., in Properties of Group III Nitrides. EMIS DataReview Series No. 11, ed. by Edgar, J.H. (INSPEC, Institution of Electrical Engineers, London, 1994) pp. 288292.Google Scholar
9 Foresi, J.S., Thesis, M.S., Boston University, 1992.Google Scholar
10 Foresi, J.S. and Moustakas, T.D., Appl. Phys. Lett. 62 (22) 2859 (1993).Google Scholar
11 Hacke, P., Detchprohm, T., Hiramatsu, K., and Sawaki, N., Appl. Phys. Lett. 63 (19) 2676 (1993).Google Scholar
12 Khan, M.R.H., Detchprohm, T., Hacke, P., Hiramatsu, K., and Sawaki, N., J. Phys. D 28 1169 (1995).Google Scholar
13 Binari, S.C., Dietrich, H.B., and Kelner, G., Electronics Lett. 30 (11) 909 (1994).Google Scholar
14 Reeves, G.K. and Harrison, H.B., IEEE Electron Device Lett. EDL–3 111 (1982).Google Scholar
15 Huang, Y., Smith, L., Kim, M. J., Carpenter, R. W. and Davis, R. F. in Evolution of Thin-Film and Surface Structure and Morphology, edited by Demczyk, B. G., Williams, E. D., Garfunkel, E., Clemens, B. M., and Cuomo, J. E. (Mat. Res. Soc. Proc. 355, Pittsburgh, PA, 1995) pp. 433439.Google Scholar
16 Lin, M.E., Ma, Z., Huang, F.Y., Fan, Z.F., Allen, L.H., and Morkoç, H., Appl. Phys. Lett. 64 (8) 1003 (1994).Google Scholar