Two-dimensional metal-semiconductor field effect transistor for ultra low power circuit applications

We describe a novel 2-dimensional metal-semiconductor field effect transistor (2-D MESFET) in which opposing Schottky side gates formed on the sidewall of a modulation-doped AlGaAs-InGaAs heterostructure modulate the channel width and the drain current. The drain current ranged from 0 to 210 μA and the maximum measured transconductance was 212 μS (212 mS/mm) at room temperature for a 1×1 micron channel. The threshold voltage was -0.45 V and the subthreshold ideality factor was 1.30. The estimated gate capacitance was 0.8 fF/μm, or about half the equivalent capacitance of conventional HFET's. The cutoff frequency fTwas estimated to be 21 GHz. The narrow channel effect, which limits the minimum power consumption in conventional FET's, is practically eliminated in this device.