Time-based micro-g accelerometer with improved damper geometry

Closed-loop pull-in time operated devices are a good alternative for high sensitivity accelerometers. The main design challenges for a pull-in time parallel-plate capacitive MEMS accelerometer are related to damping and therefore an improved damper geometry is introduced in this paper that enables the reduction of the damping forces without changing the capacitance value. MEMS structures designed and fabricated in a 60μm-thick SOI micromachining process are used to demonstrate the accelerometer time-based approach. The characteristics of this process are considered to simulate and discuss the benefits of the proposed damping-reduction geometry.