Design optimization of MEMS gyroscope for enhanced sensitivity, bandwidth and noise reduction

Abstract

The paper presents and discusses a novel methodology for enhancing the amended Figure of merit (FOM) in a MEMS-based Gyroscope device using a thick sense mass. Generally, at the design stage, the focus is on optimising individual performance parameters like sensitivity, noise, or bandwidth based on specific applications. However, maximising an integrated figure of merit (FOM) is crucial for broader applicability and resource efficiency, enabling a single sensor to perform well across diverse applications. It is shown that one can obtain a better FOM by proper design optimization and using a simple single thick sense mass than existing reported approaches. The proposed design is demonstrated to achieve maximum device capability by simultaneously considering the maximization of sensitivity, bandwidth, and noise minimisation. The theoretical model and analysis of the proposed design were validated using Coventorware and Simulink software simulations, showing very close agreement with analytical results within 5 %. Compared to existing reports on devices under identical conditions, the optimized design exhibits a 52-fold increase in FOM at the fundamental level, measured in units of m Hz/dps²mm². Deep Reactive Ion Etching (DRIE) has been proposed to be used to fabricate these devices through established processing steps, and experimental results validate and confirm the successful realization of structures for the sense mass. Additionally, we propose a new empirical relationship between sensitivity and bandwidth for improvement in device design. The effect of temperature on the thermomechanical noise is also considered. The proposed analysis provides valuable insights for MEMS gyroscope designers, aiming to enhance performance for applications such as navigation, intelligent machines and robotic systems.