Annealing effects on structural and electrical properties of Ru/Au on n-GaN Schottky contacts

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 137; no. 1; pp. 200 - 204
• Main Authors: Reddy, V. Rajagopal, Rao, P. Koteswara, Ramesh, C.K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.02.2007
• Subjects: Auger electron microscopy; I– V and C– V techniques; n-GaN; Schottky barrier height; X-ray diffraction; X-ray diffraction; Schottky barrier height; I– V and C– V techniques; Auger electron microscopy; n-GaN
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2006.11.018

Thermal annealing effects on electrical and structural properties of Ru/Au Schottky contact to n-type GaN ( n d = 4.07 × 10 17 cm −3) have been investigated using current–voltage ( I– V), capacitance–voltage ( C– V), Auger electron spectroscopy (AES) and X-ray diffraction (XRD). The Schottky barrier height of the as-deposited sample was found to be 0.75 eV ( I– V) and 0.93 eV ( C– V), respectively. It is noted that the barrier height increased when the contact was annealed at 300 °C and slightly decreased upon annealing at temperatures of 400 °C and 500 °C. The extracted Schottky barrier heights are 0.99 eV ( I– V), 1.34 eV ( C– V) for 300 °C, 0.88 eV ( I– V), 1.20 eV ( C– V) for 400 °C and 0.72 eV ( I– V), 1.08 eV ( C– V) for 500 °C annealed contacts, respectively. Further it is observed that annealing results in the improvement of electrical properties of Ru/Au Schottky contacts. Based on Auger electron spectroscopy and X-ray diffraction studies, the formation of gallide phases at the Ru/Au/n-GaN interface could be the reason for the improvement of electrical characteristics upon annealing at elevated temperatures.