Improved Switching Behavior of SiC-MOSFETs with Monolithic SiRC-Snubber Chips

In this paper, the switching behavior of SiCMOSFET modules with integrated monolithic silicon RCsnubbers (SiRC-snubber) are investigated. SiC-MOSFETs have many advantages over more common technologies e.g. SiIGBTs. One of these advantages is the high switching speed. This potential often cannot be fully utilized due to parasitic inductances with combined high overvoltages and/or EMC issues. Therefore, the switching speed has to be limited to stay inside the specs of the individual device. This limitation can be reduced using a SiRC-snubber that can be integrated inside the power module. To investigate the influence during switching, a 750 V SiC-MOSFET module with integrated SiRC-snubber soldered on the DCB is tested. The switching behavior of the SiC-MOSFET body diode with and one without SiRC-snubber is compared. The results show that oscillations and voltage overshoots during switching can be drastically reduced. Further, the power-device losses can also be reduced.