Short channel effects on gallium nitride/gallium oxide nanowire transistors

Abstract

Gallium nitride/gallium oxide GaN/Ga 2O 3 nanowire metal-oxide-semiconductor field-effect-transistors are shown to operate at an average electron velocity of ∼1.24 × 10 7 cm/s and threshold-voltage roll-off of -0.2 V as the transistor gate length L g reduced from 500 to 50 nm. Improvement of saturation current to 120 μA and unity current/power-gain cut-off frequency to 150/180 GHz is observed on L g 50 nm devices. Our study reveals the advantages of using (i) polarization-induced positive charges and high-k dielectric at the { 1 1 0 1 }GaN/{002}Ga 2O 3 interface to provide carrier confinement and to shield the drain field, and (ii) polarization-induced negative charges at the (0001)GaN/sapphire interface to form a back-barrier to suppress leakage and improve the short-channel transport properties. © 2012 American Institute of Physics.