Fabrication of a 1.7-kV Schottky barrier diode with improved forward current-voltage characteristics

This paper presents the effects of thermal annealing performed at different temperatures on the forward current-voltage (I-V) characteristics to fabricate a 1.7-kV 4H-SiC Schottky barrier diode (SBD) with improved forward performances. To optimize the thermal annealing temperature, the SBDs were characterized by using precise low-current and high-current I-V measurements, a twodiode model analysis and grazing-incidence X-ray diffraction measurements. The results showed that a degradation in the ideality factor and a dramatic decrease in the turn-on resistance began at temperature above 550 °C. In particular, the turn-on resistance for the SBD annealed at 550 °C was reduced by 32% compared to that for the SBD without thermal annealing without any degradation in the Schottky barrier height. This was attributed to an expansion of Al crystallites caused by the thermal annealing.