Ultra high switching speed 600 V thin wafer PT-IGBT based on new turn-off mechanism

A new turn-off mechanism for 600 V thin wafer PT-IGBTs (punch-through IGBTs) has been found and ultra high speed switching has been demonstrated, for the first time, in this paper. The new turn off process makes it possible to operate IGBTs in a quasi-MOSFET mode in the turn-off transient, realizing ultra high speed switching. Most of the stored carriers in the n-drift region can be automatically removed, without any additional means, in the storage time period, before the voltage recovery process. This results in extremely low dissipated power loss and substantially eliminates tail current. Furthermore, this paper described the results of numerical investigation and measured characteristics of the sustaining mode operation. When the p-emitter efficiency of thin wafer PT-IGBTs was decreased, the sustaining voltage was larger than the static breakdown voltage and most of the current was supplied by impact ionization due to poor p-n-p transistor action. Thin wafer PT-IGBTs with reduced p-emitter efficiency behave like quasi-MOSFETs.