IGBT and Free-Wheeling Diode Behavior during the Short Circuit Type III with varied Operation Conditions

In this paper, the interaction between the Insulated Gate Bipolar Transistor (IGBT) and the Free-Wheeling Diode (FWD) in the short circuit type III (SC III) failure has been studied. The influence of the different operation conditions, like the load current and temperature, are investigated. Furthermore, external factors such as gate impedance, packaging style, and the different diode technologies are discussed. Since the paralleled diode is in the conducting mode before the short circuit, the plasma inside the bipolar silicon (Si) diode and the reverse recovery behavior play essential roles in the short circuit behavior of the IGBT. Under certain conditions, the short circuit stress of the IGBT can be minor and the diode enters the regime of the dynamic avalanche. Moreover, TCAD simulations have been carried out to analyze the internal behavior of IGBT and diode during the SC type III event.