The BETA-MOSFET: A novel high-performance transistor

The bipolar enhanced transistor action (BETA)-MOSFET, operating in a mixture of FET mode and bipolar mode, has been fabricated. Unlike the lateral bipolar transistor, its base current can be automatically controlled by the gate voltage. Hence, the device operating voltage can be in a wide range and is a maximum of -4 V. It is confirmed that the device can be treated as a high-performance MQSFET in circuit analysis. Three types of device structures, with a gate-substrate contact that includes an ultrathin-film tunnel junction, are fabricated and evaluated. In the p-channel BETA-MOSFET, the drain current and the maximum transconductance are about four times those of the conventional MOSFET while maintaining the same threshold voltage. This result implies that the BETA-MOSFET with a gate length of 1.3 mu m exhibits a superior performance equivalent to a 0.1-mu m p-MOSFET. (C) 1997 Scripta Technica, Inc.