CMOS-MEMS transverse-mode square plate resonator with high Q and low motional impedance

An integrated CMOS-MEMS transverse-mode square plate resonator centered at 6.52 MHz has been demonstrated with Q's ranging from 800 to 1,900, and specifically with the lowest motional impedance of 35 kΩ compared to any other CMOS-MEMS counterparts to date by the combination of large transduction area and pull-in mechanism to achieve deep-submicron electrode-to-resonator gap spacing using a foundry-oriented CMOS-MEMS process. In addition, such a resonator is formed by metal/oxide composite structure where the residual stress often seen in CMOS layers is greatly alleviated and where SiO
₂
with positive temperature coefficient of Young's Modulus (TC
_E
) offers an effective temperature compensation scheme, therefore greatly improving its thermal stability as compared with mere-metal resonators under the same fabrication technologies.