THE MGBT - A NEW MOS-GATED POWER BIPOLAR-TRANSISTOR

A new device called the MGBT is described in which the upper regions of the device structure is conductivity-modulated by a positive feedback mechanism to give a lower on-state voltage drop compared to a power DMOSFET while having fast switching and fully gate-controlled characteristics. In the MGBT, a P+ injector coupled to the drain potential by a vertical driver DMOSFET in an emitter-switched configuration is used to inject holes which is then diverted to the entire surface region of the device by a novel cell design. 750 V MGBT devices fabricated along with DMOSFET devices on the same wafer showed 33% improvement in current density at room temperature and 46% improvement at 75-degrees-C at a forward drop of 3.5 V. The turn-off time of the MGBT was 80 ns equal to that of the DMOSFET.