Relationship between threading dislocation and leakage current in 4H-SiC diodes

The impact of threading dislocation density on the leakage current of reverse current-voltage (I–V) characteristics in Schottky barrier diodes (SBDs), junction barrier Schottky diodes, and p-n junction diodes (PNDs) was investigated. The leakage current density and threading dislocation density have different positive correlations in each type of diode. Consequently, the correlation in SBDs is strong but weak in PNDs. Nano-scale inverted cone pits were observed at the Schottky junction interface, and it was found that leakage current increases in these diodes due to the concentration of electric fields at the peaks of the pits. The threading dislocations were found to be in the same location as the current leakage points in the SBDs but not in the PNDs.