CMOS-MEMS resonators and their applications

This paper reports on the recent progress of the high-Q integrated micromechanical resonator, oscillator, and filter using the “CMOS-MEMS technology” to enable monolithic integration of MEMS and IC. The paper scope covers three major parts, including (i) the fabrication technologies of the CMOS-MEMS resonators and their associated circuitry; (ii) the performance enhancement of the resonators on motional impedance, quality factor, power handling, thermal stability, frequency tuning, and parasitic feedthrough; (iii) the implementation of the CMOS-MEMS resonators for frequency generation (i.e., oscillators) and frequency selection (i.e., filters) functionalities. In the first part, various fabrication technologies in the 0.35μm and 0.18μm CMOS technology nodes are presented, showing their own features and advantages. In the second part, several strategies in design aspects and material point of views were proposed to enhance the performance of the CMOS-MEMS resonators. In the last part, designs and experimental results of the CMOS-MEMS oscillator and filter are presented. We take full advantage of the IC and semiconductor strength in Taiwan to develop several CMOS-MEMS resonator platforms towards single-chip implementation for timing reference, oscillator, filter, and sensor applications.