Unified view on energy and electrical failure of the short-circuit operation of IGBTs

This work investigates the relation of the two destruction modes, the so-called energy destruction and the electrical destruction, during short-circuit operation of an Insulated Gate Bipolar Transistor (IGBT). The critical energy as a function of the short circuit current reveals a kink indicating the transition between two different failure modes. The failure signatures show that energy destruction takes place at lower currents and electrical destruction at higher currents. This supports the hypothesis that there is a huge current range with non-destructive filaments at low dc-link voltages. For both destruction mechanisms, the final failure occurs locally. For the energy destruction, the current crowding happens very late during the runaway itself, whereas in the case of an electrical destruction, filaments are formed mainly by an electrical mechanism leading to a stronger local self-heating. Both mechanisms take place far above the safe operating area of the chip.