Investigation of the Four-Gate Action in hbox G⁴ -FETs

The four-gate silicon-on-insulator transistor (G/sup 4/-FET) combines MOS and JFET actions in a single transistor to control the drain current. The various operation modes of the G/sup 4/-FET are analyzed, based on the measured current-voltage, transconductance and threshold characteristics. The main parameters (threshold voltage, swing, mobility) are extracted and shown to be optimized for particular combinations of gate biasing. Numerical simulations are used to clarify the role of volume or interface conduction mechanisms. Besides excellent performance (such as subthreshold swing and transconductance) and unchallenged flexibility, the new device has the unique feature to allow independent switching by its four separate gates, which inspires many innovative applications.