Shunting patterns occurring in epitaxial 6H-SiC p-n structures for high-voltage rectifiers

Results are presented of a study of the forward and reverse currents in 6H-SiC p-n structures grown by chemical vapor deposition (CVD). The thickness of the n-type layer was 10–25 μm and the doping level 2–10 1015 cm−3. Most of the p-n structures exhibiting considerable forward and reverse excess currents, the extent of their relationship was investigated. Based on an analysis of the different features of the current-voltage characteristics, an assumption was made that these excess currents are due to the presence of resistive and rectifying shunts paralleling with the 6H-SiC p-n junction. The physical nature and the characteristic size of the shunts are discussed.