Tuning fork silicon angular rate sensor with enhanced performance for automotive applications

This paper reports on a silicon angular rate sensor designed for automotive applications like overroll protection and electronic skidding protection. The sensor is based on a tuning fork principle with the tines being piezoel ectrically excitated perpendicular to the wafer surface. Due to the Corioli s effect, an angular rate parallel to the axis of the stem generates a peri odic torque, which results in a torsional oscillation of the stem. This tor sional oscillation is detected with an implanted piezoresistor located in t he middle of the stem. A slot in the center of the stem enhances the shear stress at the read-out piezoresistor position resulting in a higher sensiti vity. The latest sensor design with a split electrode allows an electronic compensation of mechanical imbalance in order to reduce the sensor offset a nd offset drift. Additionally, this electrode configuration can generate a periodic torque to perform a permanent test of the sensor functioning and t he sensitivity during operation. (C) 2000 Elsevier Science S.A. All rights reserved.