1.3 mm2 Nav-Grade NEMS-Based Gyroscope

• Published in: Journal of microelectromechanical systems Vol. 30; no. 4; pp. 513 - 520
• Main Authors: Gadola, Marco, Buffoli, Andrea, Sansa, Marc, Berthelot, Audrey, Robert, Philippe, Langfelder, Giacomo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Coriolis force; Couplings; Demodulation; Gauges; Gyroscopes; inertial navigation; Low pressure; Nanoelectromechanical systems; Navigation; NEMS; Optimization; Q-factor; Quadratures; stability; Stability criteria; Voltage control
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2021.3088940

The research reports the design and experimental results of novel gyroscopes based on nano-resistive sensing, capable to meet navigation grade specifications within a sensor footprint of 1.3 mm 2 and a total silicon structural volume of 0.026 mm 3 only. A significant increase of the scale-factor is obtained through a combination of (i) optimization of the Coriolis force transduction into a stress on the resistive gauges, (ii) increase of the drive motion amplitude and (iii) increase of the current through the sensing gauges. Combined with low-pressure eutectic packaging, this enables approaching the thermomechanical noise limits of the sensor at about 0.004 <inline-formula> <tex-math notation="LaTeX">^{\circ }/\surd </tex-math></inline-formula> hr. At the same time, electronics is developed with minimum demodulation phase errors, thus enabling optimized closed-loop quadrature compensation and minimization of drift effects. Thanks to the inherent rejection of parasitic couplings and associated drifts of the used technology, the overall stability reaches 0.02 °/hr on average on 6 samples. These performances are demonstrated for a 30-Hz system bandwidth and few hundred dps input range over several samples. Navigation grade performance are confirmed by additional in-operation experiments like gyrocompassing and in-run 9-minute long angle measurements from rate integration. [2021-0073]