Achieving Below 200ppm Scale Factor Temperature Stability in an am Gyroscope with On-Chip Stress Sensing

For the first time, we demonstrate a stress-based compensation that improves the scale factor stability of an AM, mode split gyroscope by more than 15x compared to the common temperature calibration. We test our gyroscope by exposing it to controlled temperature cycles within the 25-90°C range while maintaining a dithered rate table input. We have equipped our double-ring, 3.2mm-diameter, 58kHz gyroscope with eight 45°-apart capacitive stress sensors. This arrangement allows us to measure the nonuniform distribution of the stresses across the device as well as their residuals over temperature. Thanks to stress sensing, the proposed compensation captures the hysteresis effects induced by the residual stresses, achieving 125ppm (peak-to-peak) and single-digit ppm Allan deviation scale factor temperature stability.