A Low Noise Bulk Micromachined Gyroscope with Symmetrical and Decoupled Structure

This paper presents a low noise bulk micromachined gyroscope. The design of frame and independent beams reduces the mechanical coupling between the drive mode and sense mode, and facilitate the frequency match of two modes. The gyroscope with a 100-120-mum-structure thickness and an aspect ratio about 12 is fabricated by DRIE technology and silicon-glass anodic bonding, which provides a high sense capacitance about 2.1 pF and a weighty proof mass about 1.27 mg. Resonant frequencies of the drive and sense mode are measured to be 1610 and 1676 Hz, respectively. The gyroscope can achieve a 2.97 muN electrostatic driving force by applying of a 6V AC and 15V DC bias voltage on the driving electrodes. The thermal-mechanical noise floor is estimated to be about 0.12deg/h/Hz^frac12 at atmospheric pressure