Turn-off failure mechanism analysis of Punch Through Trench IGBT under clamped inductive switching operation

Abstract

The investigation of the internal physical behaviour of the Punch Through Trench Insulated Gate Bipolar Transistor, under Clamped Inductive Switching turn-off has been done. A two dimensional mixed circuit and device simulation tool has been used and two switching configurations have been carried out: a non-destructive and a destructive turn-off switchings have been analyzed and compared to each other. The results show that the failure is delayed after the turn-off and is due to a thermal runaway phenomenon initiated by the temperature rise within the device during the switching transient.

A step by step methodology to analyze the IGBT failure mechanisms under short circuit and turn-off inductive conditions using 2D physically based device simulation

“…Three different failure configurations are presented as examples of the methodology application to reveal the different failure origins. The first and the second one are failures occurring respectively during turn-on and few microseconds after turn-off [6] under short circuit conditions whereas the third example is a failure occurring several microseconds after inductive load turn-off [8].…”

“…When we observe the figure 17, it is possible to say that the failure mechanism is linked to a thermal runaway initiated by a strong impact ionization. A more complete analysis is given in detail in [8].…”

“…During high electrical and thermal stresses applied in many power module applications, different failures can occur, for example, under short circuit [1][2][3][4][5][6][7] and inductive switching conditions [8][9][10]. Those failures are often illustrated as drastic increasing of the total current in the power components, leading in many cases to the destruction of the device.…”