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

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

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
Volume33
Issue number5
Publication statusPublished - 2004 May 1
Externally publishedYes

Fingerprint

Ohmic contacts
low resistance
Structural properties
electric contacts
Electric properties
electrical properties
Annealing
annealing
Photoelectron spectroscopy
X ray spectroscopy
photoelectric emission
Aurothioglucose
Rhenium
Core levels
thermal degradation
rhenium
Auger electron spectroscopy
Contact resistance
Titanium
contact resistance

Keywords

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

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

Cite this

Electrical and structural properties of low-resistance Ti/Al/Re/Au ohmic contacts to n-type GaN. / Reddy, V.; Kim, Sang Ho; Seong, Tae Yeon.

In: Journal of Electronic Materials, Vol. 33, No. 5, 01.05.2004, p. 395-399.

Research output: Contribution to journalArticle

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AB - 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.

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