Abstract

The Schottky diode behaviors of the TiWNx and the WNx Schottky contacts to n-GaN were investigated at different annealing temperatures. Both TiWNx and WNx films were deposited by reactive dc sputtering method. The X-ray diffraction data and secondary ion mass spectroscopy analysis showed that no interfacial phases were formed during the thermal treatment process. The WNx/n-GaN contact exhibited excellent electrical characteristics even after rapid-thermal annealed up to 850? for 10 seconds. The ideality factor and barrier height remained 1.09 and 0.80 eV respectively after 850? annealing. However, the TiWNx/n-GaN contact was thermally stable only up to 650? annealing, the values of the ideality factor and the barrier height were 1.14 and 0.76 eV respectively after 650? annealing and started to degrade when annealed at higher temperatures. The deterioration of the TiWNx/n-GaN contact at higher temperatures was due to the inter-diffusion of the TiWN film and the GaN material.