Design of a high-sensitivity sub-40µg capacitive accelerometer using a Multi-Project Wafer process

This paper presents the design of a high-sensitivity parallel plates accelerometer intended to inertial navigation. Common issues of the parallel plates topology have been addressed to improve the sensor capacitive sensitivity and resolution. A sensitivity of 350 pF/g and a sub-40μg/sqHz resolution have been achieved through simulation. As this sensor will be operated in closed-loop mode with electrostatic force feedback, the small displacements between plates allow the use of low voltages in the feedback loop. The device is being fabricated under a Multi-Project Wafer program; the use of a limited fabrication process added several difficulties in the design process.