Thermal Annealing Behaviour on Electrical Properties of Pd/Ru Schottky Contacts on n-Type GaN

Authors N. Nanda Kumar Reddy, V. Rajagopal Reddy
Sri Venkateswara University, Department of Physics, Semiconductor Devices Lab, Tirupati-517502, India
Issue Volume 3, Year 2011, Number 1, Part 5
Dates Received 04 February 2011, in final form 30 November 2011, published online 08 December 2011
Citation N. Nanda Kumar Reddy, V. Rajagopal Reddy, J. Nano- Electron. Phys. 3 No1, 921 (2011)
PACS Number(s) 85.30.Hi, 85.30.Kk
Keywords Schottky barrier diode, Thermal annealing temperature, I-V avd C-V characteristics, Leakage current (3) , Barrier height (11) .
We have investigated the electrical properties of Pd/Ru Schottky contacts on n-GaN as a function of annealing temperature by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The Schottky barrier height of the as-deposited Pd/Ru contact is found to be 0.67 eV (I-V) and 0.79 eV (C-V), respectively. Measurements showed that the Schottky barrier height increased from 0.68 eV (I-V) and 0.80 eV (C-V) to 0.80 eV (I-V) and 0.96 eV (C-V) as the annealing temperature is varied from 200 °C to 300 °C. Upon annealing at 400 °C and 500 °C, the Schottky barrier height decreased to 0.73 eV (I-V) and 0.85 eV (C-V) and 0.72 eV (I-V) and 0.84 eV (C-V), respectively. It is noted that the barrier height further decreased to 0.59 eV (I-V) and 0.72 eV (C-V) when the contact is annealed at 600 °C. The change of Schottky barrier heights and ideality factors with annealing temperature may be due to the formation of interfacial compounds at the Ru/Pd/n-GaN interface.

List of References