Characterisation of iridium Schottky contacts on n -Al x Ga 1− x N

The electrical characteristics of Ir Schottky contacts on n-type AlxGa1−xN (x=0, 0.10, 0.20, 0.25) grown by MOCVD on sapphire substrate are investigated. The barrier heights are obtained from current–voltage (I–V) and capacitance–voltage (C–V) measurements and are found to increase with aluminium composition. The effect of thermal annealing on barrier height of Ir Schottky diodes on Al0.25Ga0.75N is also studied. Only slight degradation in Schottky barrier height is observed after annealing the Ir-Schottky diodes at 850°C for 30 s.