Rapid thermal annealing effects on the electrical and structural properties of Ru/V/n-InP Schottky barrier diode

• Annealing effects on electrical and structural properties of Ru/V/n-InP SBD are studied.
• Maximum barrier height is obtained on Ru/V/n-InP SBD after annealing at 400 °C.
• Interface state density of Ru/V/n-InP SBD decreases upon annealing at 400 °C.
• Indium phases are responsible for increase in barrier height after annealing at 400 °C.
• Overall surface morphology of the SBD is considerably smooth at elevated temperatures.

A Ru/V/n-InP Schottky barrier diode (SBD) is fabricated and investigated its electrical and structural properties as a function of annealing temperature. Measurements showed that the barrier height (BH) of the as-deposited Ru/V/n-InP SBD is found to be 0.83 eV (I–V) and 1.03 eV (C–V). Experimental results indicate that the SBD with high BH and low ideality factors (0.87 eV (I–V), 1.20 eV (C–V), and 1.12) can be achieved after annealing at 400 °C for 1 min in N2 atmosphere. Further, it is observed that the BH slightly decreases to 0.85 eV (I–V) and 1.09 eV (C–V) upon annealing at 500 °C. The BH, ideality factor and series resistance are also determined by Cheung’s functions and Norde method. Further, the energy distribution of interface state density of Ru/V/n-InP SBD is calculated from the forward bias I–V characteristics as a function of annealing temperature. It is found that the interface state density decreases upon annealing at 400 °C and then slightly increases after annealing at 500 °C. The AES and XRD results revealed that the formation of indium phases at the Ru/V/n-InP interface could be the reason for the increase of BH upon annealing at 400 °C. The formation of phosphide phases at the interface may be the cause for the decrease of BH after annealing at 500 °C. The overall surface morphology of Ru/V Schottky contacts is considerably smooth at elevated temperatures.