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

TL;DR

This paper presents a semi-insulating 4H-SiC lateral bulk acoustic wave resonator with high quality factors, demonstrating its potential for quantum applications involving color centers and mechanical tuning.

Contribution

It introduces a novel monolithic SiC resonator with improved Q factors and optical access, suitable for quantum spintronics and MEMS applications.

Findings

Resonator exhibits Q factors above 3000 at 300 MHz

Acoustic reflector improves Q by 22% at resonance

Optical access enables quantum measurement setup

Abstract

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.