Ohmic contacts to GaN with rapid thermal annealing

L. W. Chi, K. T. Lam, Y. K. Kao, F. S. Juang, Y. S. Tsai, Y. K. Su, S. J. Chang, C. C. Chen, J. K. Sheu

Research output: Contribution to journalConference article

1 Citation (Scopus)

Abstract

This research attempted to use metals with lower work functions, such as Ti, Al, to form ohmic contacts to n-GaN. Then we used metals with higher work functions, such as Ni, Pd, Pt, and Au to form ohmic contacts to p-GaN. The work functions of these metals indeed influence the performance of ohmic contacts, indicating that the Fermi level of GaN is unpinned. The specific contact resistance measured and calculated by TCL model, was 2.35×10-3 Ωcm2 for as-deposited Ti/Al on GaN. After RTA processes at different temperatures in the range of 400 to approximately 900 °C, the minimum ρc of 7.4×10-5 Ωcm2 can be obtained for RTA temperature of 600 °C. The oxidized Ni/Au contact exhibited the lowest contact resistance of 1.02×10-2 Ωcm2, among Ni/Au, Pd/Au, Pt/Au contact schemes on p-GaN. It was also observed that the I-V curves of the triple-layer contact, Pt/Ni/Au, was near-linear while the others were rectifying even after annealing.

Original languageEnglish
Pages (from-to)224-233
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3938
Publication statusPublished - 2000 Jan 1
EventLight-Emitting Diodes: Research, Manufacturing, and Applications IV - San Jose, CA, USA
Duration: 2000 Jan 262000 Jan 27

Fingerprint

Ohmic contacts
Rapid thermal annealing
Annealing
electric contacts
Metals
Contact
Contact resistance
Contact Form
Contact Resistance
annealing
contact resistance
Fermi level
metals
Lowest
Temperature
Curve
temperature
Range of data
curves
Model

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Chi, L. W., Lam, K. T., Kao, Y. K., Juang, F. S., Tsai, Y. S., Su, Y. K., ... Sheu, J. K. (2000). Ohmic contacts to GaN with rapid thermal annealing. Proceedings of SPIE - The International Society for Optical Engineering, 3938, 224-233.
Chi, L. W. ; Lam, K. T. ; Kao, Y. K. ; Juang, F. S. ; Tsai, Y. S. ; Su, Y. K. ; Chang, S. J. ; Chen, C. C. ; Sheu, J. K. / Ohmic contacts to GaN with rapid thermal annealing. In: Proceedings of SPIE - The International Society for Optical Engineering. 2000 ; Vol. 3938. pp. 224-233.
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Chi, LW, Lam, KT, Kao, YK, Juang, FS, Tsai, YS, Su, YK, Chang, SJ, Chen, CC & Sheu, JK 2000, 'Ohmic contacts to GaN with rapid thermal annealing', Proceedings of SPIE - The International Society for Optical Engineering, vol. 3938, pp. 224-233.

Ohmic contacts to GaN with rapid thermal annealing. / Chi, L. W.; Lam, K. T.; Kao, Y. K.; Juang, F. S.; Tsai, Y. S.; Su, Y. K.; Chang, S. J.; Chen, C. C.; Sheu, J. K.

In: Proceedings of SPIE - The International Society for Optical Engineering, Vol. 3938, 01.01.2000, p. 224-233.

Research output: Contribution to journalConference article

TY - JOUR

T1 - Ohmic contacts to GaN with rapid thermal annealing

AU - Chi, L. W.

AU - Lam, K. T.

AU - Kao, Y. K.

AU - Juang, F. S.

AU - Tsai, Y. S.

AU - Su, Y. K.

AU - Chang, S. J.

AU - Chen, C. C.

AU - Sheu, J. K.

PY - 2000/1/1

Y1 - 2000/1/1

N2 - This research attempted to use metals with lower work functions, such as Ti, Al, to form ohmic contacts to n-GaN. Then we used metals with higher work functions, such as Ni, Pd, Pt, and Au to form ohmic contacts to p-GaN. The work functions of these metals indeed influence the performance of ohmic contacts, indicating that the Fermi level of GaN is unpinned. The specific contact resistance measured and calculated by TCL model, was 2.35×10-3 Ωcm2 for as-deposited Ti/Al on GaN. After RTA processes at different temperatures in the range of 400 to approximately 900 °C, the minimum ρc of 7.4×10-5 Ωcm2 can be obtained for RTA temperature of 600 °C. The oxidized Ni/Au contact exhibited the lowest contact resistance of 1.02×10-2 Ωcm2, among Ni/Au, Pd/Au, Pt/Au contact schemes on p-GaN. It was also observed that the I-V curves of the triple-layer contact, Pt/Ni/Au, was near-linear while the others were rectifying even after annealing.

AB - This research attempted to use metals with lower work functions, such as Ti, Al, to form ohmic contacts to n-GaN. Then we used metals with higher work functions, such as Ni, Pd, Pt, and Au to form ohmic contacts to p-GaN. The work functions of these metals indeed influence the performance of ohmic contacts, indicating that the Fermi level of GaN is unpinned. The specific contact resistance measured and calculated by TCL model, was 2.35×10-3 Ωcm2 for as-deposited Ti/Al on GaN. After RTA processes at different temperatures in the range of 400 to approximately 900 °C, the minimum ρc of 7.4×10-5 Ωcm2 can be obtained for RTA temperature of 600 °C. The oxidized Ni/Au contact exhibited the lowest contact resistance of 1.02×10-2 Ωcm2, among Ni/Au, Pd/Au, Pt/Au contact schemes on p-GaN. It was also observed that the I-V curves of the triple-layer contact, Pt/Ni/Au, was near-linear while the others were rectifying even after annealing.

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Chi LW, Lam KT, Kao YK, Juang FS, Tsai YS, Su YK et al. Ohmic contacts to GaN with rapid thermal annealing. Proceedings of SPIE - The International Society for Optical Engineering. 2000 Jan 1;3938:224-233.