Design of tri-axis capacitive MEMS accelerometer based on single mass

The design, manufacture and test of a tri-axis capacitive MEMS accelerometer based on the single mass are presented. This acceleration sensor takes advantage of single mass structure to reduce the MEMS dimensions and decrease the cost. To match the sensitivity design requirement, the differential capacitive detection is utilized, and the sensitivity coupling problem of three orthogonal axes is avoided. The mass and comb finger structure are based on the EPI-poly process to realize the 18 μm thickness. The detection capacitance, sensitivity and reliability are improved, and the mechanical noise is decreased. The ANSYS simulation results show that the sensor is consistent in three axes with good anti jamming capability. The testing results agree with the simulation data. Thanks to the simple structure and process, the single-mass tri-axis capacitive accelerometer can be widely used in consumer electronics applications.