Silicon carbide electromechanical resonators

Abstract

Silicon carbide (SiC) flexural-mode resonators have been fabricated and actuated. Single-clamped beam (cantilever) and circular (ring) structures have been fabricated with top electrodes made of aluminium (Al). Ring structures have been shown to achieve higher resonant frequencies, in the megahertz range, compared to cantilevers. The bimorph Al/SiC structures have been actuated electrothermally by applying one input voltage to the Al electrodes. Electrothermal mixing of two input frequencies has been performed by applying two voltages showing that the devices can be used to convert an input frequency to a higher or lower one. Moreover, lead zirconium titanate (PZT) electrodes have been fabricated on top of SiC cantilevers. The ability of driving the PZT/SiC cantilevers piezoelectrically has been demonstrated by applying an input voltage to the PZT electrodes. The devices’ resonance has been detected electrically by measuring the electrode impedance. An enhancement of the electrical output has been obtained by decreasing the feedthrough capacitance. The results presented can be used for the implementation of SiC micro electromechanical mixer-filters with electrothermal actuation and piezoelectric sensing with robust and reliable characteristics.