We fabricated 4H-SiC PiN diodes to analyze the correlation between the reverse characteristics, including current-voltage and failure characteristics, and defects. The leakage current and electroluminescense (EL) were measured at prebreakdown voltages. The diodes were etched by using molten KOH, and the locations of etch pits were compared with those of hot spots emitting during the EL measurements. The results showed that the reverse leakage current of a diode having defects in the p− junction termination extension (JTE) was at most 26 times higher than that of a diode having defects in an active area. The breakdown voltages of the diodes with threading screw dislocations (TSDs) and threading edge dislocations (TEDs) were reduced by 15.5% and 6.5%, compared with those of a diode without defects. In addition, the diodes were found to be destroyed due to weak edge termination resulting from misalignment and large pits.