Design, fabrication and characterization of a low-noise Z-axis micromachined gyroscope

This paper presents the design, fabrication and characterization of a low-noise Z-axis micromachined gyroscope. A triple-mass scheme is adopted to obtain a decoupled mode and matched vibration structure. The gyroscope was fabricated based on a 30-mu m silicon on insulator wafer. A DRIE, lag-effect-based, dicing-free process was used to easily and rapidly create the gyroscope devices without requiring normal dicing. The fabricated gyroscopes were vacuum packaged (pressure of approximately 2,000 Pa) and tested. The measured power spectral density of the noises is as low as 17.5 mu V/v Hz, and the resolution of the fabricated gyroscope is 7.1 x 10-4 degrees/s root Hz (2.52 degrees/h/root Hz).