Investigations on the nonidealities in Pd/n-GaN Schottky diodes grown by MOCVD

The effect of ammonia flow rate on the device characteristics of Pd/n-GaN Schottky diodes is discussed. The carrier concentration and hall mobility of the as grown epilayers were found to decrease with an increase in the V/III ratio. Current–Voltage (I–V) barrier height initially decreases and then increases with an increase in V/III ratio. The ideality factor and leakage current decreases with an increase in the V/III ratio. The Capacitance–Voltage (C–V) measurements of small area contacts showed a large variation in the slope of the lines of A2/C2 vs. V plot. I–V–T measurements revealed that the ideality factor and the reverse leakage current increases with temperature confirming that the conduction mechanism is through trap-assisted tunneling process or deep center hopping conduction. Device parameters of GaN Schottky diodes were found to be strongly affected by the variation in localized structural changes induced by V/III ratio.