A Z-axis MEMS gyroscope with improved sensitivity

Abstract

Modification of mechanical structure of a MEMS gyroscope can significantly improve stability and sensitivity of the sensor. The parameters, which can affect sensitivity and stability of a vibratory inertial sensor, include signal coupling between the drive and sense parts, different damping sources such as air-damping and thermo-elastic damping, and fabrication tolerance. In this paper the mechanical structure of a decoupled Z-axis MEMS gyroscope is modified and the sensitivity of the drive resonance frequency and amplitude to geometrical variations and fabrication tolerance is studied. In addition to the drive part, the capacitive sensing method is modified to improve the capacitance change of the sense combs.