Concurrent Enhancement of Q and Power Handling in Multi-Tether High-Order Extensional Resonators

In this paper we demonstrate that quality factor (Q) and power handling, two inherently divergent characteristics of a resonator, can be improved simultaneously by designing high-order harmonic resonant structures anchored with multiple tethers. We show that in thin-film piezoelectric-on-substrate (TPoS) resonators, the quality factor is significantly altered by varying the resonator´s thickness, but the resonator´s power handling is often traded off for the higher Q. Q´s measured from TPoS resonators fabricated on a 30µm thick silicon substrate are up to 3 times higher than the values measured for devices on 20µm thick substrate while maximum deliverable power (at the bifurcation point) to the same device is reduced from 2.5dBm to −0.3dBm. In contrast, it is observed that the maximum deliverable power in a multi-tether ∼1GHz resonator is enhanced by more than 5dBm compared to an identical single-pair tethered resonator (7dBm versus 1.9dBm) and the Q is also increased by 55%.