Charge trapping in nitrogen implanted 6H-SiC n+p junctions

Silicon carbide is one of the wide bandgap semiconductors that has been projected to have performances exceeding those of silicon and GaAs for high temperature and high-voltage power applications. Properties such as high electric breakdown field, high thermal conductivity, large saturated electron drift velocity, and excellent thermal stability make SiC a material of choice for high-power and high temperature operation. In SiC device fabrication, ion implantation of donor and acceptor impurities into SiC wafers is necessary to realize planar junctions, ohmic contacts, and numerous type of transistors. Although many efforts in improving the percentage of dopants activation and to decrease residual damages created during implantation process have been reported, the electrical behavior of the implanted SiC junctions has not been extensively studied. In this paper, we report a charge trapping phenomenon, unreported previously, in the n⁺p junctions of 6H-SiC formed by nitrogen implantation. This charge trapping causes excessive leakage current that decays slowly (~msec) during reverse recovery