Electro-thermal instability in multi-cellular Trench-IGBTs in avalanche condition: Experiments and simulations

Abstract

This paper reports on the results of a study on electro-thermal instability induced in multi-cellular TrenchIGBTs in avalanche condition. Experimental measurements, made on T-IGBTs, show possible inhomogeneous current distribution under Unclamped Inductive Switching (UIS) confirmed by transient infrared thermography measurements. Together with this, an analytical modeling of avalanche behavior has been included in a compact electro-thermal simulator to study the interaction between a large numbers of elementary cells of TIGBTs forced in avalanche condition. Electro-thermal simulations qualitatively replicate the possible inhomogeneous operation observed experimentally. Finally a possible theoretical interpretation of the instability in avalanche condition for T-IGBT is given.

Multidirectional development of IGBTs and diodes: low loss and tough but gentle (user‐friendly) power devices

“…27). This method is beneficial to detections of fabrication defects instead of high current module tests like an SCSOA or a large current UIS [98,99]. Once the avalanche occurs around defects, the V CE rise halts due to charging the extra capacitor C. At the stop-moment of the current shunting to the C, small but all the current immediately flows into the IGBT.…”

3D electro-thermal simulations of wide area power devices operating in avalanche condition

“…With this value of current in fact, device operates in negative differential resistance region and correct behavior of the implemented simulator can be evaluated in this condition. As effect of negative resistance, current distribution becomes non uniform during the time [10][11][12]. Initially device starts with uniform temperature and a current which is slightly non uniform due to differences in the layout and to parasitic elements.…”

“…[12][13][14][15]. In this case the final profile of the current density shows a creation of a hot-spot and all the current flows in a very small area, just after 6 ls.…”

Cell pitch influence on the current distribution during avalanche operation of trench IGBTs: Design issues to increase UIS ruggedness

“…Together with the need of increased performances there has recently been an increased request of reliability and, in recently many cases, ruggedness during avalanche operation. Recent the importance of investigating the avalanche ruggedness of IGBTs has been thoroughly investigated [1][2][3][4][5][6][7][8][9][10][11] by means of theoretical, numerical and experimental evidences. These investigations have demonstrated that failure during avalanche operation usually occur when current filaments are present in the device active area or in the termination region.…”