Electrical and structural properties of low-resistance Ti/Al/Re/Au ohmic contacts to n-type GaN

V. Reddy, Sang Ho Kim, Tae Yeon Seong

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11 Citations (Scopus)


Titanium (15 nm)/aluminum (60 nm)/rhenium (20 nm)/gold (50 nm) ohmic contacts to moderately doped n-type GaN (4.07×1018 cm -3) have been investigated as a function of annealing temperature. It is shown that the current-voltage (I-V) characteristics of the contacts are improved upon annealing at temperatures in the range of 550-750°C. Specific contact resistance as low as 1.3×10-6 Ωcm2 is obtained after annealing at 750°C for 1 min in a nitrogen ambient. X-ray photoemission spectroscopy (XPS) results show that the Ga 2p core level for the sample annealed at 750°C shifts toward the high binding side by 0.71 eV compared with that of the as-deposited one. It is also shown that the contact does not seriously suffer from thermal degradation even when annealed at 750°C for 30 min. Based on Auger electron spectroscopy (AES), glancing angle x-ray diffraction (GXRD), and XPS results, possible explanations for the annealing-induced improvement of the ohmic behavior are described and discussed.

Original languageEnglish
Pages (from-to)395-399
Number of pages5
JournalJournal of Electronic Materials
Issue number5
Publication statusPublished - 2004 May
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by Korea Research Foundation Grant No. KRF-2003-042-D00131.


  • Auger electron spectroscopy
  • Glancing angle x-ray diffraction
  • Ohmic contacts
  • X-ray photoemission spectroscopy
  • n-type GaN

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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