Characteristics and analysis of 4H-SiC PiN diodes with a carbon-implanted drift layer^*

The characteristics of 4H-SiC PiN diodes with a carbon-implanted drift layer was investigated and the reason of characteristics improvement was analyzed. The forward voltage drops of the diodes with carbon-implanted drift layer were around 3.3 V, which is lower than that of devices without carbon implantation, the specific-on resistance was decreased from 9.35 to 4.38 mΩ·cm² at 100 A/cm², and the reverse leakage current was also decreased. The influence of carbon incorporation in the SiC crystalline grids was studied by using deep-level transient spectroscopy (DLTS). The DLTS spectra revealed that the Z_1/2 traps, which were regarded as the main lifetime limiting defects, were dramatically reduced. It is proposed that the reduction of Z_1/2 traps can achieve longer carrier lifetime in the drift layer, which is beneficial to the performance of bipolar devices.