Failure mechanism of trench IGBT under short-circuit after turn-off

Power semiconductor devices under short-circuit are submitted to high current and high voltage simultaneously that induce high electrical and thermal stresses. Several types of event leading to failure can appear under short circuit conditions in IGBT depending on the device structure, current load and voltage levels. One particular short circuit event appears once the device has turned off. After a while, the device seems to be turned on again and the current increases drastically leading to the device failure. The purpose of this study is to investigate the behaviour of Trench IGBT under such failure by the mean of 2D physically-based device simulations in order to bring some useful data for the device optimization. The physics allows to provide essential points of view on the failure description. In the proposed study, the failure does not come from latch-up but from the parasitic NPN bipolar component due to an enhancement of the conduction under thermal effect.