MOSFET-mode ultra-thin wafer PTIGBTs for soft switching application $theory and experiments

We have previously proposed and analyzed the MOSFET-mode operation of ultra-thin wafer PTIGBTs in (T. Matsudai et. al., Proc. of ISPSD´02, p.258). The present paper, for the first time, presents an analytical theory of MOSFET-mode operation, and shows that the safe operating area is determined by a mechanism similar to the second breakdown of npn bipolar transistors. The present paper also experimentally demonstrates, for the first time, that the MOSFET-mode IGBTs are strongly effective for soft switching applications. The developed MOSFET-mode 900 V 60 A thin wafer trench gate PTIGBTs have reduced turn-off loss by 55% at 125°C, compared with the conventional (4th generation) soft switching PTIGBTs.