Beta Gallium Oxide ($\beta$-Ga2O3) Vibrating Channel Transistor

Abstract

We report on the first demonstration of an ultra-wide bandgap (UWBG), single-crystal $\beta$ -Ga 2 O 3 vibrating channel transistor (VCT), with all-electrical actuation and detection enabled by efficient vibration-induced channel conductance modulation. Given the challenges in making functional transistors in nanometer-thick $\beta$ -Ga 2 O 3 with appreciable on-state current and gating effect, directly coupling motion into transistors of this UWBG crystal has been elusive and not been explored yet. Here, we engineer the thickness of suspended $\beta$ -Ga 2 O 3 channel to attain a favorable threshold voltage ( $\vert V_{\mathrm{th}}\vert ), and operate the device in the subthreshold regime for optimal electromechanical coupling. A lithographically defined local gate device structure on insulating substrate and frequency modulation (FM) mixing techniques are employed for the VCT to suppress parasitic background, leading to enhanced transduction of the first $\beta$ -Ga 2 O 3 VCT resonance at ∼26MHz. The realization of all-electrical readout of $\beta$ -Ga 2 O 3 VCT resonators with local gates paves a way for integrating $\beta$ -Ga 2 O 3 nanoelectromechanical resonators with individual device addressability into the rapidly developing $\beta$ -Ga 2 O 3 electronics for on-chip sensing, communication, and computing functionalities.