A new hybrid VDMOS-LIGBT transistor

A p-channel vertical DMOSFET structure coupled with a lateral IGBT (insulated-gate bipolar transistors) path is described. External resistors are placed in series with either the collector terminal (the bipolar-enhanced MOSFET (BIENFET) mode) or the drain terminal (the substrate collector-shorted (SCOSH) LIGBT mode) to vary the degree of minority-carrier injection. This creates the opportunity to obtain a device with externally programmable forward-drop/switching speed tradeoff. The device is shown experimentally to have forward drops close to those of vertical and lateral IGBTs and turn-off times close to that of MOSFETs. Typical forward drops at 93 A/cm/sup 2/ range from 3-4 V and corresponding turn-off times from 4.3 to 0.22 mu s when the drain resistor is varied. This device is considered particularly attractive as a high-frequency and high-voltage power switch.<
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