A CMOS-MEMS Resonator Integrated System for Oscillator Application

This paper focuses on the design and development of a CMOS-MEMS resonator integrated with an on-chip amplifier with emphasis on its single-chip frequency reference oscillator implementation. A flexural-mode ring resonator with a desired mode shape featuring an inherent fully-differential mode of mechanical operation is designed using both analytical and finite element models. Two such resonators in low- and high-frequency domains, centered at 1.39 and 9.34 MHz respectively, are individually modeled using first principals, equations, and simulation tools to evaluate and improve device performance. In this paper, the device is also shown to offer a potential benefit of capacitive feedthrough cancelation up to 30 dB attributed to differential signaling scheme. Subsequently, both rapidly prototyped devices integrated with their on-chip transimpedance amplifiers are demonstrated using a commercially available TSMC 0.35-μm CMOS technology. A low-frequency resonator integrated with its on-chip amplifier exhibited decent overall performance capabilities in terms of much higher transmission spectra (closer to 0 dB), greater feedthrough suppression, higher signal-to-feedthrough ratio (35 dB), and exact phase shift (0°) at resonance frequency, therefore being a potential candidate for a single-chip oscillator system.