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 thickness of the resonator, but the power handling of the resonator is often traded off for the higher Q. Quality factors measured from TPoS resonators fabricated on a 30 μm thick silicon substrate are up to 3 times higher than the values measured for devices on 20 μm thick substrate while maximum deliverable power (at the point of bifurcation) to the same device is reduced from 2.5 dBm to -0.3 dBm. In contrast, it is observed that the maximum deliverable power in a multi-tether ~1GHz resonator is enhanced by more than 5 dBm compared to an identical single-pair tethered resonator (7dBm versus 1.9dBm) and the quality factor is also increased by 55%.