Evidence on the impact of T-shaped tether variations on Q factor of bulk-mode square-plate resonators

This paper reports evidence from measurements that anchor design has no obvious impact on the quality factor (Q) of a square-plate resonator vibrating in the Lamé mode. This observation is attributed to uniquely locating the anchors at the nodes positioned conveniently at the corners. The measured Q and eigenfrequency show no dependence on variations in the length of the T-shaped tethers. In contrast, the same variations were shown to significantly affect both Q and eigenfrequency when the resonator was excited in the square-extensional (SE) mode. These trends were consistently observed between measurements on two different fabricated SOI dies. For further validation, the measured correlation between the eigenfrequency and tether length for both eigenmodes agree well with those predicted by finite-element (FE) simulations in COMSOL.