Experimental demonstration of dual gate MOS thyristor

A new device concept, called the dual gate MOS thyristor (DGMOS), is introduced for simultaneously obtaining the low on-state voltage drop of a thyristor together with the fast turn-off speed of an IGBT and the results of measurement performed on devices with 900 V forward blocking capability are reported for the first time. Its on-state voltage drop (Von) was 1.30V at a current of 12 A (71.4 A/cm²) with a turnoff loss (Eoff) of 114 μJ. These values of Von, Eoff indicate a much superior trade-off characteristic when compared to the IGBT in the voltage resonant circuit. Furthermore, the ability to turn-off the DGMOS is found to be improved by a homogeneous current distribution at the turn-off stage via reducing a sheet resistance of the gate poly-crystalline silicon layer and increasing a transition time from the thyristor mode operation to the IGBT mode