Mitigation of AO spurious modes in AlN MEMS resonators with SiO2 addendums

This paper presents an AO spurious mode mitigation technique for Aluminum Nitride (AlN) laterally vibrating resonators (LVRs). The technique attaches two identical SiO2 addendums to the lateral edges of the suspended AlN resonator body to shift the asymmetrical (AO) spurious modes away from the intended SO mode vibration. The AlN resonators with SiO2 addendums have been investigated theoretically with finite element analyses (FEAs) and validated experimentally. The measured response of the fabricated devices has shown successful mitigation of AO spurious mode without the compromise of electromechanical coupling, kt2, and quality factor Q.