High-Q and Low-Motional Impedance Piezoelectric mems Resonator through Mechanical Mode Coupling

A high-Q and low-motional impedance (R-m) resonator is achieved by mechanically coupling a low-impedance piezoelectric length extensional-mode resonator with two high-Q single-crystal silicon (SCS) Lame-mode resonators. The mass-weighted quality factor relationship between the mode-coupled resonator and the individual resonating elements has been demonstrated. By properly adjusting the mass ratio of the individual resonating elements, the mode-coupled resonator achieves a record high-quality factor of 172105 for piezoelectric resonators whereas the R-m is maintained as low as 350 Omega at 19.7 MHz. Our results offer opportunity to use MEMS resonators in high-performance temperature-compensated MEMS oscillators (TCMOs) and oven-controlled MEMS oscillators (OCMOs), making these devices a potential candidate for communication and intelligent vehicle applications.