Bidirectional lateral insulated gate transistors operated in controlled latchup mode

The use of the lateral insulated transistor (LIGT) as an integrable MOS controlled power switch has been reported recently. The mode of operation is based on a MOS transistor turning on and subsequently saturating a bipolar transistor. Latchups of the parasitic thyristor are to be avoided so that the gate exerts full control at all times. It is shown that the latchup mode of operation can be controlled by the gate with proper design of the device structure. The advantages of operating the device in latchup mode are higher current capabilities and lower `on´ voltages than available in other modes of operation. The bidirectional LIGT is symmetrical in that it conducts current and block voltage in both directions. It can be readily implemented with conventional BICMOS process without any additional process steps. The operation, fabrication, and performance of the bidirectional device are briefly described