Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-21T17:12:51.923Z Has data issue: false hasContentIssue false
  • English
  • Français

Electric and Morphology Studies of Ohmic Contacts on AlGaN/GaN

Published online by Cambridge University Press:  15 March 2011

V. Tilak ,
R. Dimitrov ,
M. Murphy ,
B. Green ,
J. Smart ,
W.J. Schaff ,
J.R. Shealy  and
L.F. Eastman
V. Tilak
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
R. Dimitrov
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
M. Murphy
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
B. Green
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
J. Smart
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
W.J. Schaff
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
J.R. Shealy
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
L.F. Eastman
Affiliation:
School of Electrical Engineering, Cornell University, Ithaca, NY -14850
Get access

Abstract

AlGaN/GaN is a promising system for high power electron devices. Quality of ohmic contacts is a critical parameter in determining the performance of the device. Although we have achieved a transfer resistance (Rc) of 0.35Δmm and ρc of 9.5×10−7 Δcm−2 the morphology and edge acuity of the contacts are poor. The standard ohmic contact recipes consist of a combination of Titanium and Aluminum with Nickel and/or Gold. This is annealed at 800°C-950°C [1-5]. In this work we study ohmic contacts on unintentionally doped Al0.3Ga0.7N/GaN system. We look at ratios of Ti/Al from 0 to 2 to determine which is the optimum ratio in terms of surface morphology and electrical characteristics. From our studies we conclude that morphology of a Ti/Al contact is good over a ratio of 0.3 and the contact resistance is minimized at a Ti/Al of 0.6. The ohmic contacts are improved electrically if a layer of gold is added on top. The best electrical contacts however were obtained with a four layer recipe of Ti/Al/Ti/Au, which gave contact resistance (Rc) around 0.45Δmm, but the morphology of the contacts was poor.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 622: Symposium T – Wide-Bandgap Electronic Devices , 2000 , T7.4.1
Copyright
Copyright © Materials Research Society 2000

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. Liu, Q. Z., Yu, L. S., Deng, F., Lau, S. S., Chen, Q., Yang, J. W., and Khan, M. A., Appl. Phys. Lett., 71 (12), 1658 (1997).Google Scholar
2. Eastman, L., Chu, K., Schaff, W., Murphy, M., Weimann, N. G., Eustis, T., MRS Internet J. Nitride Semicond. Res. 2, 17(1997).Google Scholar
3. Ruvimov, S., Liliental-Weber, Z., Washburn, J., Duxstad, K. J., Haller, E. E., Fan, Z.-F., Mohammad, S. N., Kim, W., Botchkarev, A.E., and Morkoç, H., Appl. Phys. Lett., 69 (11), 1556 (1996).Google Scholar
4. Wu, Y.-F., Keller, B. P., Keller, S., Kapolnek, D., Kozodoy, P., Denbaars, S. P., and Mishra, U. K., Appl. Phys. Lett., 69 (12), 1438 (1996).Google Scholar
5. 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
6. Nguyen, N. X., Micovic, M., Wong, W. S., Hasimoto, P., McCray, L. M., Janke, P., and Nguyen, C., Electronics Lett., 36(5), 468 (2000)Google Scholar
7. Murphy, M. J., Chu, K., Wu, H., Yeo, W., Schaff, W. J., Ambacher, O., Eastman, L. F., Eustis, T. J., Silcox, J., Dimitrov, R., Stutzmann, M., Appl. Phys. Lett., 75 (23), 3653 (1999).Google Scholar
8. Eastman, L. F., Tilak, V., Smart, J., Green, B., Dimitrov, R., Chumbes, E. M., Kim, H. T., Ambacher, O., Weimann, N., Prunty, T., Murphy, M., Schaff, W., Shealy, J. R., Submitted to IEEE Trans. Electron Dev., April 2000.Google Scholar
9. Ambacher, O., Foutz, B., Smart, J., Shealy, J. R., Weimann, N. G., Chu, K., Murphy, M., Sierakowski, A. J., Schaff, W. J., Eastman, L. F., Dimitrov, R., Mitchell, A., and Stutzmann, M., J. Appl. Phys. 87(1), 334 (2000).Google Scholar