Comparison of the Forward Voltage Drop of Si and SiC High Voltage Diodes

To obtain a high coefficient of efficiency of a converter, the components used to build it should be well chosen. Significant part of the losses is due to the power semiconductor switches. For the same break down voltage, SiC bipolar device have significantly thinner lightly doped drift region (n- base) and therefore low switching losses and also low voltage drop in the drift region.  The forward voltage drop of a bipolar device is sum of the drift region voltage drop and the junction voltages. The junction voltages of Si device are significantly smaller as compared to the SiC devices since their bandgap is smaller. Therefore, for not so high voltage devices (< 4 kV), the forward voltage drop will be smaller for Si compared to the SiC devices, while for high voltage devices it is opposite. In this work, physics-based models of Si and SiC diodes are used to calculate their forward voltage drop for different breaking voltage and the simulation results are compare to determine a border between  Si and SiC devices.