Effect of temperature treatment on Au/Pd Schottky contacts to 4H-SiC

Au/Pd/SiC Schottky barrier contacts have been formed on n-type 4H-SiC grown by sublimation epitaxy. The effect of annealing temperature on the electrical properties of these contacts was studied using I-V and C-V measurements. The barrier height was found to increase slightly from 1.14 eV for as-deposited contacts to 1.2 eV after annealing at 500 deg C, while the more pronounced effect was observed with decrease of the ideality factor. Auger analysis was used to study the metallurgy of the annealed contacts. Strong diffusion between Au and Pd was established after 500 deg C anneal, while the Pd/SiC interface remained almost steep. The electrical properties of annealed contacts have been study during the thermal treatment at temperatures up to 350 deg C and prolonged ageing at 300 deg C and 400 deg C in nitrogen.