IGBT current filamentation observation by segmented collector sensing under UIS condition

Inhalt:
Current filamentation during the avalanche period of insulated-gate bipolar transistors (IGBTs) has been investigated using various approaches including TCAD simulations and temperature distribution measurements, since the phenomena can be an origin of chip current capability lowering with the parasitic thyristor latching-up due to the strongly localized current. This paper reports, for the first time, the current filamentation is directly measured as collector currents of segmented metallization areas of an IGBT chip. The experimental results show that the filament moves across the segmented areas with couple of micro second as the transition time and the transitions are not identical for the repeated tests even the circuit condition is the same.