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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.

This work aims at extending the predictive simulation technique for cosmic ray-induced failure analysis from Si PiN diodes [1] to SiC PiN diodes. Accurate 3D cylindrical-symmetric transient simulations were performed with a minimum mesh size of 20nm at the center track of the impinging ion and a maximum time step of 0.1ps during the development of the ion-induced transient current. We made a comparative study between a SiC PiN diode and a Si PiN diode with the same blocking voltage of 1.5kV, using the same heavy ion transportation models. In the simulation, we observed different ion-induced current transients, differing not only in the peak value of the current, but also in its duration. Due to different physical mechanisms, the dependence of the ion-induced current on the reverse pre-bias voltage and the numerical mesh adaptations are also different. Eventually, we brieflydiscuss electro-thermal simulations, which indicate once more that the ion-induced transient current in the SiC PiN diodes under consideration is primarily drift current and involves only negligible impact ionization.