Micro-machined resonant accelerometer with high sensitivity

A resonant accelerometer with high sensitivity, fabricated through MEMS bulk-silicon processes, is proposed in this paper. The external acceleration can be transferred into the frequency shift of the resonant beams which is double-clamped by the proof mass and the anchor. To improve the sensitivity of the accelerometer, a micro leverage force amplifying mechanism is adopted, from which the transformation efficiency between the external acceleration and the axial stress of the resonant beam would be improved obviously. MEMS bulk-silicon processes were used on single one wafer to fabricate the sensor chip. The electromagnetic excitation and detection was used to make the closed-loop control of the sensor easier. Experimental results show that the Q-factor of the resonant beam is about 450 and the sensitivity of the accelerometer is about 1900 Hz/g.