MEMS disk resonator gyroscope with integrated analog front-end

We present a 2 mm diameter, 35 μm thick disk resonator gyro (DRG) fabricated in <111> silicon with integrated 0.35 μm CMOS analog front-end circuits in the Invensense NF process. This process incorporates a wafer-level vacuum seal, yielding a quality factor (Q) of 2800 at the DRG's 78 kHz resonance frequency. After performing electrostatic tuning to enable mode-matched operation, this DRG achieves a 63 μV/°/s sensitivity. Resonator vibration in the sense and drive axes is sensed using capacitive transduction, and amplified using a low-noise, on-chip integrated circuit. This allows the DRG to achieve Brownian noise-limited performance. The angle random walk (ARW) is measured to be 0.01 (˚/sec)/√Hz and the bias instability is 30 °/hr.