Sensitivity Enhancement of Capacitive MEMS Accelerometer by Design of the Device Geometry

In current study the improvement of the device sensitivity for an area-changed capacitive accelerometer is presented using optimization of the device structure. The proof mass of the device was designed with few parallel fingers connected with each other and suspended over the fixed electrodes which are by means of flexible spring like mechanical beams anchored onto the substrate. With application of acceleration the maximum displacement experienced by the proof mass is determined for the particular structure. The length and width of the connected beams were varied and response was simulated using ANSYS software. From results of different device geometry measurement sensitivity of the device are analyzed and discussed, along with suggested steps for improvement of sensitivity. A signal conditioning circuit to convert the capacitance change obtained from change in deflection of proof mass of the device structure to a voltage change is also presented. These findings may be useful to design capacitive MEMS accelerometer of improved sensitivity.