Effect of Thermal Annealing on Ni/Au Contact to p-GaN

다국어 초록 (Multilingual Abstract)

We deposited Ni (13 nm) / Au (30 nm) layers on p-GaN by using the dc sputtering method in order to produce low-resistivity Ohmic contacts. The Ni (13 nm) / Au (30 nm) contact layers were annealed in air for 15 min at various temperatures. The electrical and the structural properties of the Ni/Au contact to p-GaN were investigated. The current-voltage measurement showed that the resistance of the as-deposited sample was very high. However, the sample annealed at 600 ℃ showed Ohmic-like behavior with a specific contact resistance of 1.9 × 10−3 cm2. Further increasing the temperature caused the Ohmic-like behavior to be degraded. Transmission electron microscopy and Auger electron spectroscopy were used to characterize the interfacial structure between the Ni/Au electrode and the p-GaN layers. The Ni layer was in contact with the p-GaN before annealing. However, after annealing, the Au layer had diffused from the top layer to the interface. The Au layer on the p-GaN surface resulting from the indiffusion of Au atoms during
annealing may contribute to effective Ohmic contact formation.

다국어 초록 (Multilingual Abstract)

We deposited Ni (13 nm) / Au (30 nm) layers on p-GaN by using the dc sputtering method in order to produce low-resistivity Ohmic contacts. The Ni (13 nm) / Au (30 nm) contact layers were annealed in air for 15 min at various temperatures. The electrical and the structural properties of the Ni/Au contact to p-GaN were investigated. The current-voltage measurement showed that the resistance of the as-deposited sample was very high. However, the sample annealed at 600 ℃ showed Ohmic-like behavior with a specific contact resistance of 1.9 × 10−3 cm2. Further increasing the temperature caused the Ohmic-like behavior to be degraded. Transmission electron microscopy and Auger electron spectroscopy were used to characterize the interfacial structure between the Ni/Au electrode and the p-GaN layers. The Ni layer was in contact with the p-GaN before annealing. However, after annealing, the Au layer had diffused from the top layer to the interface. The Au layer on the p-GaN surface resulting from the indiffusion of Au atoms during
annealing may contribute to effective Ohmic contact formation.

참고문헌 (Reference)

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