Temperature Dependence of the Bipolar Activation and the Leakage Currents of 10 kV 4H-SiC JBS-Diodes

The activation of bipolar conduction was investigated for two 4H-SiC 10 kV JBS-diodes which differ in the area ratio between p-doped and n-doped regions (Ws/WPin). Quasi-static measurements at low electric current densities (j < 2.5 Acm-2) were performed in a temperature range between 25°C and 500°C. The lower ratio (Ws/WPin) leads to a higher threshold voltage. On the other hand lower electric power density is neccessary to trigger temperature enhanced bipolar activation. Moreover, the lower ratio improves the leakage currents in blocking direction. Dynamic surge current investigations were performed in a temperature range between 25°C and 250°C. The turning voltages, which indicate the transition from unipolar to bipolar conduction, are lower for the diode with smaller ratio (Ws/WPin) but the self-heating of the device is more severe in comparison to the other diode with the larger ratio. Both devices are stable under extreme conditions (high temperatures/ surge current) and exhibit special benefits for different applications.