Formation of low resistance Ti/Al-based ohmic contacts on (11-22) semipolar n-type GaN

Jae Seong Park, Jaecheon Han, Tae Yeon Seong

Research output: Contribution to journalArticle

7 Citations (Scopus)


The electrical properties of Ti/Al-based ohmic contacts to (0001) c-plane and (11-22) semipolar n-type GaN were investigated as a function of annealing temperature. The electrical properties of both c-plane Ti/Al/Au and semi-polar Ti/(Ta)/Al/Au contacts became improved upon annealing at 600 °C for 1 min. The specific contact resistances of the 600 °C-annealed c-plane Ti/Al/Au, semi-polar Ti/Al/Au, and semipolar Ti/Ta/Al/Au contacts were 3.2 × 10<sup>-4</sup>, 1.5 × 10<sup>-4</sup>, and 4.8 × 10<sup>-5</sup> Ωcm<sup>2</sup>, respectively. The X-ray photoemission spectroscopy (XPS) results showed that the Ga 2p core level for the c-plane samples experienced a smaller shift toward the conduction band than that for the semipolar samples. The XPS depth profile results exhibited that the semipolar samples contained more interfacial oxygen than the c-plane samples. Oxygen was present in the form of Al-oxide at the interface region, but as oxygen atoms in the GaN surface region. On the basis of the electrical and XPS results, the annealing-induced improvement of the electrical properties was described in terms of the formation of donor-like defects.

Original languageEnglish
Pages (from-to)167-171
Number of pages5
JournalJournal of Alloys and Compounds
Publication statusPublished - 2015 Dec 15


  • Light-emitting diode
  • Ohmic contact
  • Semipolar GaN
  • Ti/Al

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Chemistry
  • Metals and Alloys

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