A TPoS MEMS Resonator With Enhanced Anchor Quality Factor Exploiting One-Dimensional Phononic Crystal Tether

Exploiting elastic wave propagation isolation mechanism-based support tethers is one of the commonly key techniques to enhance the quality factor (Q) of microelectromechanical systems (MEMS) resonators. Phononic crystals (PnCs) can generate bandgaps (BGs) to act as an elastic wave barrier when embedded into these tethers of the resonators. This paper proposes a four-circle-holed PnC (4CH_PnC) strip-shaped support tether to improve the Q in terms of anchor quality factor (QANC) of the designed resonator. The length extensional mode resonator vibrates at 110 MHz. The BG generated by the 4CH PnC has a width of 9.81 MHz and covers this resonant frequency. The QANC of the resonator is investigated according to the variation of the unit cell number (UCN) of the 4CH_PnC. Furthermore, this QANC is also compared to three benchmark support tethers to verify its effectiveness in suppressing/eliminating the anchor dissipation. In addition, the change of the BG formation of the 4CH_PnC with its dimension parameters is also evaluated. The finite element simulation results show that the QANC of the resonator with 4CH_PnC is considerably higher boosted than three other benchmarks. Specifically, this QANC equals 1.99 x 10 15 compared to 3485.18, 802.06, and 6540.80 of three benchmarks circle-shaped stub PnC (C_PnC), square-shaped stub PnC (S_PnC), and ring-shaped stub PnC (CH_PnC), respectively. Only the 4CH PnC completely eliminates the anchor energy dissipation flow as its UCN reaches 19 cells. Therefore, the anchor loss suppression of the proposed PnC is superior to that of three benchmark tethers.