Study of Titanium Tungsten Nitride and Tungsten Nitride Schottky Diodes on n-GaN

摘要

The Schottky diode behaviors of the TiWN_x and the WN_x Schottky contacts to n-GaN were investigated at different annealing temperatures. Both TiWN_x and WN_x 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 WN_x-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 TiWN_x-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 TiWN_x-GaN contact at higher temperatures was due to the inter-diffusion of the TiWN film and the GaN material.