THE MULTIPLE-GATE MOS-JFET TRANSISTOR

Abstract

A new SOI device, the MOS-JFET, has been developed that combines two different transistors, JFET and MOSFET, superimposed in a single silicon island so that they share the same body. A unique attribute of the MOS-JFET is that it can be viewed as a four gate transistor (two side junction-based gates, the top MOS gate, and the back gate activated by SOI substrate biasing). Each of these four gates can control the conduction characteristics of the transistor. This novel transistor's multiple gate inputs give rise to exciting circuit opportunities for analog, RF, mixed-signal, and digital applications. Measured results of MOS-JFET transistors, fabricated in a conventional partially-depleted SOI technology, demonstrate that the device is fully operational. From the experiments and systematic 2-D simulations, typical regions of operation are identified. These results indicate that optimum performance is reached when the MOS and junction field-effects are combined.