A Bent-TBTF Resonant MEMS Accelerometer using Auxiliary Supporting Beams

This letter demonstrates a high-responsivity piezoelectric resonant MEMS accelerometer using a bent-TBTF resonator. Different from the conventional bent-beam resonant accelerometers, the proposed device uses two auxiliary supporting beams that can be designed to control the initial bending shape of the TBTF resonator and thus alter its force sensing behavior. These auxiliary supporting beams provide a new design freedom for manipulating the linear operation range of the device, which was considered an inherent issue for the resonant accelerometers based on bent-beam sensing. The validity of the proposed design is verified by comparing the measured results to the finite-element simulations. The demonstrated bent-TBTF resonant accelerometer exhibits responsivity as large as 2.92 kHz/g with footprint of 3.1 mm × 1.4 mm. By proper design of aluminum coverage of the auxiliary supporting beams, the proposed device achieves good nonlinearity factor of 2.7% in the interested acceleration range from -6 g to 6 g.