The effects of structural defects and the interface inhomogeneity on the leakage current of Ni/4H-SiC SBDs have been investigated. I-V characteristics are measured mainly at 100 degreesC to assess the high-temperature performance. Measured SBDs have a large variation of leakage current over several orders of magnitude. It is hard to find any clear relationship between the leakage current density and the number of dislocations. The measured I-V characteristics can be separated into the main Schottky barrier height (phi(B) = 1.7 eV) component and the low-phi(B) component. The leakage current significantly increases when the barrier height for the low-phi(B) component (phi(LBH)) is lower than 1.1 eV.