  600V/20A 4H-SiC Schottky barrier diodes (SBD) were fabricated to investigate
the effect of key processing steps, especially before and after a formation of
Schottky contact, on the electrical performances of SBD and on a long-term
reliability. The results show that 4H-SiC SBDs, subjected to a hydrogen-ambient
annealing at 470oC for 10min and sacrificial treatment right after ion
activation, exhibited low forward voltage drop (VF) at a rated current of 20A,
higher blocking voltage of 800V, and very short reverse recovery time of
17.5ns. Despite a harsh reverse bias condition and temperature, a long-term
reliability test shows that changes in forward voltage drop and reverse leakage
current (IR) were 0.7% and 8.9% and that blocking voltage was enhanced. This is
attributed to a stabilized interface between passivation layer and SiC that is
caused by aging.
