A new ohmic contact scheme for gallium nitride is presented. The use of Nitride-forming metal Over Gallide-forming metal, “NOG”, can modify the thermodynamic activity of N and Ga near the interface. This in turn can modify the near-surface point defect concentrations, particularly the vacancies of Ga and N. The principle of this contact scheme was shown to be consistent with results from Ni/Au, Ni/Zn-Au, Ta/Ti, and Ni/Mg/Ni/Si contacts. In the present study, the “NOG” scheme was used to design Ni/Ti/Au and Ni/Al/Au metallization, and addition of Ti and Al nitride-forming metals to the Ni gallide-forming metal led to lower but still high contact resistance. Ti was shown to be better than Al as the nitride-forming metal based on the decrease of resistance in as deposited contacts. Compared to Ni/Au, four times more current was measured in Ni/Ti/Au contacts to p-GaN after anneal at 300°C for 5min. However the addition of the Ti nitride-forming metal led to lower stability at 500°C.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
M. Suzuki, T. Kawakami, T. Arai, S. Kobayashi, Y. Koide, T. Uemura, N. Shibata and M. Murakami, Appl. Phys. Lett., 1999, 74, 275
J.-K. Ho, C.-S. Jong, C. C. Chiu, C.-Y. Chen, Appl. Phys. Lett., 1999, 74, 1275
A. K. Fung, J. A. Borton, M. I Nathan J. M. V. Hove and R. Hickman, J. Elec. Mater., 1999, 28, 572
T. Kim, M. C. Yoo and T. Kim, III-V nitrides, MRS Symp. Proc., 1997, 449, 1061
H. Ishikawa, S. Kobayashi, Y. Koide, S. Yamasaki, S. Nagai, J. Umezaki, M. Koike and M. Murakami, J. of Appl. Phys., 2, 1997, 81, 1315
D. J. King, L. Zhang, J. C. Ramer, S. D. Hersee and L. F. Lester, III-V nitrides, MRS Symp. Proc. 1997, 468, 421
J. K. Kim, J.-L. Lee, J. W. Lee, H. E. Shin, Y. J. Park and T. Kim, Appl. Phys. Lett., 1998, 73, 2953
T. Kim, J. Khim, S. Chae and T. Kim, III-V nitrides, MRS Symp. Proc., 1997, 468, 427
T. Mori, T. Kozawa, T. Ohwaki, Y. Taga, S. Nagai, S. Yamasaki, S. Asami, N. Shibata and M. Koike, Appl. Phys. Lett., 1996, 69, 3537
M. C. Yoo, J. W. Lee, J. W. Myoung, K. H. Shim and K. Kim, MRS Symp. Proc., 1996, 423, 131
J.-S. Jang, I.-S. Chang, H.-K. Kim, T.-Y. Seong, S. Lee and S.-J. Park, Appl. Phys. Lett. 74, 70(1999)
D. H. Youn, M. Hao, H. Sato, T. Sugahara, Y. nao and S. Sakai, Jpn. J. Appl. Phys. 37, 1768(1998)
S. E. Mohney and X. Lin, Journal of Electronic Materials, 1996, 25, 811
S. E. Mohney, B. P. Luther, T. N. Jackson and M. A. Khan, MRS Symp. Proc. 395, 843(1996)
P.H. Holloway, T.-J. Kim, J.T. Trexler, S. Miller, J.J. Fijol, W.V. Lampert and T.W. Haas, Appl. Surf. Sci., 1997, 117/118, 362
J. I. Pankove, GaN and Related Materials, ed. S. J. Pearton, Gordon and Breach Science Publishers, Amsteredam, Netherlands, 1(1997)
Y. Fukai, Metal-Hydrogen System-basic bulk properties, Springer-Verlag, 31(1993)
L. F. Lester, J. M. Brown, J. C. Ramer, L. Ahang, S. D. Hersee and J. C. Zolper, Appl. Phys. Lett. 69, 2737(1996)
Z. F. Fan, S. N. Mohammad, W. Kim, O. Aktas, A. E. Botchkarev and H. Mokoc, Appl. Phys. Lett. 68, 1672(1996)
M. E. Lin, Z. Ma, F. Y. Huang, Z. F. Fan, L. H. Allen and H. Morkoc, Appl. Phys. Lett. 64, 1003(1994)
About this article
Cite this article
Liu, B., Ahonen, M.H. & Holloway, P.H. A Thermodynamic Approach to Ohmic Contact Formation to p-GaN. MRS Online Proceedings Library 595, 1178 (1999). https://doi.org/10.1557/PROC-595-F99W11.78