Direct photo emission motion observation of current filaments in the IGBT under avalanche breakdown condition

Many recent studies have been reported that the current distribution has non-uniformity in IGBT under Unclamped inductive switching (UIS) condition. Those discussions are based on the calculation result performed using device simulators. And, the observation of thermal action of device has been reported by using the IR thermography. The non-uniform temperature distribution on chip and thermal map change at every several micro second periods. In this study, time resolved emission (TRE) microscopy was used to get highly precise data. The probability distribution of current in the IGBT under UIS condition was observed. Also, a change of current distribution dependent on the time and motion of current concentration were detected. These areas of high current density existence probability move along termination region of device 1.75μs after avalanche breakdown with damping. This is the first study to show the direct motion observation of photon emission from the current fllamentation in IGBT under avalanche breakdown condition.