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 articlepeer-review

1 Citation (Scopus)


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
Publication statusPublished - 2000
EventLight-Emitting Diodes: Research, Manufacturing, and Applications IV - San Jose, CA, USA
Duration: 2000 Jan 262000 Jan 27

All Science Journal Classification (ASJC) codes

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


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