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

Abstract

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 f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> was 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.