Asymmetric Double‐Gate β‐Ga₂O₃ Nanomembrane Field‐Effect Transistor for Energy‐Efficient Power Devices

Abstract

Abstract The ultra‐wide bandgap and cost‐effective melt‐growth of β‐Ga 2 O 3 ensure its advantages over other wide bandgap materials, and competitive electrical performance has been demonstrated in various device structures. In this paper, an asymmetric double‐gate (ADG) β‐Ga 2 O 3 nanomembrane field‐effect transistor (FET) comprised of a bottom‐gate (BG) metal‐oxide field‐effect transistor and a top‐gate (TG) metal‐semiconductor field‐effect transistor (MESFET) is demonstrated. Schottky contact properties are validated by characterizing the lateral Schottky barrier diode (SBD), which exhibits high rectification ratio and low ideality factor. The top‐gate β‐Ga 2 O 3 MESFET shows reasonable electrical performance with a high breakdown voltage, as anticipated by three terminal off‐state breakdown measurement. These properties are further enhanced by double‐gate operation, and superior device performance is demonstrated; positive‐shifted threshold voltage and reduced subthreshold slope enable the asymmetric double‐gate β‐Ga 2 O 3 FET to operate at low power, and almost twice as much transconductance is demonstrated for high‐frequency operation. These results show the great potential of asymmetric double‐gate β‐Ga 2 O 3 FETs for energy‐efficient high‐voltage and ‐frequency devices with optimal material and structure co‐designs.