Semi-insulating 4H-SiC lateral bulk acoustic wave resonators

Silicon carbide (SiC) excels in its outstanding mechanical properties, which are widely studied in Microelectromechanical systems (MEMS). Recently, the mechanical tuning of color centers in 4H-SiC has been demonstrated, broadening its application in quantum spintronics. The strain generated in a mechanical resonator can be used to manipulate the quantum state of the color center qubit. This work reports a lateral overtone mechanical resonator fabricated from a semi-insulating (SI) bulk 4H-SiC wafer. An aluminum nitride (AlN) piezoelectric transducer on SiC is used to drive the resonance. The resonator shows a series of modes with quality factors (Q) above 3000. An acoustic reflector positioned at the anchor shows a 22% improvement in the Q at 300 MHz resonance and suppresses the overtone modes away from it. This monolithic SiC resonator allows optical access to the SiC color centers from both sides of the wafer, enabling convenient setup in quantum measurements.