Leakage currents in 4H-SiC JBS diodes

Leakage currents in high-voltage 4H-SiC diodes, which have an integrated ($p$–$n$) Schottky structure (Junction Barrier Schottky, JBS), have been studied using commercial diodes and specially fabricated (based on a commercial epitaxial material) test Schottky diodes with and without the JBS structure. It is shown that (i) the main role in reverse charge transport is played by SiC crystal structure defects, most probably, by threading dislocations (density $\sim$10$^4$ cm$^{-2}$), and (ii) the JBS structure, formed by the implantation of boron, partially suppresses the leakage currents (by up to a factor of 10 at optimal separation, 8 $\mu$m between local $p$-type regions).