Dislocation defect based model analysis for the pre-breakdown reverse characteristics of 4H-SiC p⁺n diodes

The pre-breakdown reverse characteristics of 4H-silicon carbide diodes were studied to determine the effects of the presence of dislocations and traps in the material. The mathematical model developed showed that the SiC diode reverse characteristics are primarily controlled by the impact ionization process for the materials containing dislocation defects as well as for the defect-free samples. Results show significant increases in the device current in the presence of dislocations. These results would indicate that the materials have softer threshold and lower hold-off capabilities.