Thermally induced variation in barrier height and ideality factor of Ni/Aucontacts to p-GaN

In this paper, we describe the change in barrier heights (phi(B)) and ideal ity factors (n) of Ni/Au contacts to p-GaN determined from current-voltage measurements as a result of (a) rapid thermal annealing between 400-700 deg rees C under flowing nitrogen, and (b) testing at temperatures of 20-300 de grees C. The lowest barrier height and ideality factor values were obtained from samples annealed at 500-600 degrees C. These results provide supporti ng evidence that thermal processing helps to remove contaminants at the con tact-GaN interface, thus decreasing effective barrier height and consequent ly, contact resistance.