This paper reviews the development of silicon resonant accelerometers from 1987 to 2022. For more than 30 years, silicon resonant accelerometers have developed into varieties of structures based on different sensing methods. In the beginning, resonant accelerometers were reported to realize acceleration measurements by detecting the frequency shifts of resonators. A variety of advancements have emerged in the realm of accelerometers, encompassing various aspects such as resonator diversity, enhancements in scale factor, expanded sensing orientations, reduced temperature sensitivity, and the integration of CMOS technology. Furthermore, innovative accelerometer designs have harnessed mode-localized phenomena, synchronization techniques, and parametric modulation, with the overarching goal of enhancing their performance and expanding their applicability. This paper reviews and analyzes the performances and structures of a range of silicon resonant accelerometers over the past three decades, providing a detailing reference and guidance for researchers in this field. 2023-0166

Influences of the feedthrough capacitance on weakly coupled micromechanical resonators are theoretically analyzed and experimentally observed using current vector analysis and the Nyquist plots method for the first time. By analyzing the equivalent electric model of the weakly coupled resonators with feedthrough capacitance, it is found that the existence of the feedthrough capacitance will lead to frequency asynchronization and measurement error of the amplitude ratio of the mode localization based sensors. The variations of the transmission responses of the weakly coupled resonators with the influence of the feedthrough capacitance are experimentally demonstrated. The frequency asynchronization became less than 2.3 ppm, down from the previous 55.6 ppm, and the measurement error of the amplitude ratio was reduced from 25.9% to approximately 0 after compensating the feedthrough capacitance using the method presented in the paper. This enhancement lays the foundation for the accurate measurement of the eigenstate and the amplitude ratio of the mode localization based sensors.

This paper describes a novel MEMS resonant accelerometer based on two weakly coupled resonators (WCRs) using the phenomenon of mode localization. To the best of the authors' knowledge, it is the first time that this principle is experimentally demonstrated for an accelerometer. When acceleration acts on the two proof masses, there will be a differential electrostatic stiffness perturbation introduced on the WCRs, which leads to mode localization and mode shape change. Therefore, the acceleration can be sensed by measuring the amplitude ratio shift. The measured relative shift in amplitude ratio (~312162 ppm/g) is 302 times higher than the shift in resonance frequency (~1035 ppm/g).

A simple, low‐cost and reliable dicing‐free silicon‐on‐insulator (SOI) process is presented for solving three major challenges in manufacturing the microelectromechanical systems devices, i.e. stiction, notching and dicing damage. In this process, the cavity is used and patterned on the handle layer to solve the stiction problem, and the exposed oxide is removed in hydrofluoric acid (HF) solution before deep reactive ion etching (DRIE) on the structure layer to eliminate the notching effect's impact. The dies are attached temporally to a designed frame by the silicon dioxide. After removing the oxide using HF solution, the dies are separated from the wafer cleanly without dicing damage. The layout design rules on the front side and backside patterns are established. Furthermore, a grooved carrier wafer with specific design rules was introduced to enhance the yield rate of the process. Finally, a tuning fork gyroscope was fabricated to demonstrate the proposed fabrication process and a yield rate of over 81% was achieved. The process solves the stiction, notching and dicing damage problems only involving the apparatus associated with lithography and DRIE, offering an economic and complete SOI process solution.

This paper establishes a bias contribution model for a micromachined Coriolis vibratory gyroscope (MCVG). Eight bias sources, including stiffness imbalance, mass imbalance, and oscillation of the sense mode itself with their contributions, were analyzed and calculated. The calculation methods for key parameters, such as coupling stiffness, coupling damping, and offsets of center of mass based on the established process imperfection model, are presented in detail. Finally, the total bias of the MCVG is measured with an error of 18% compared with the theoretically calculated bias using the model. The acceptable error range of the bias model provides a solution to predict the bias behavior in the design stage before the costly fabrication.