Design and fabrication of a MEMS capacitive accelerometer with fully symmetrical double-sided H-shaped beam structure

• We design a MEMS capacitive accelerometer with fully symmetrical double-sided H-shaped beam.
• A simplified analytical model of the H-shaped beam-mass structure and numerical simulations are presented.
• The fabrication process flow of accelerometer is presented in detail.
• Primary characterization of the accelerometers is performed.

This paper presents a MEMS capacitive accelerometer with fully symmetrical double-sided H-shaped beam structure. The fully symmetrical structure is fabricated from a single double-device-layer SOI wafer, which has identical buried oxide layer and device layer on both sides of a thick handle layer. A large proof mass with through wafer thickness (560 μm) is fabricated in this process. Two layers of single crystal silicon H-shaped beams with highly controllable dimension suspend the proof mass from both sides. The resonance frequency of the accelerometer is measured in open loop system by a network analyzer. The quality factor and the resonant frequency are 106 and 2.24 kHz, respectively. The accelerometer with open loop interface circuit is calibrated on B&K Vibration Transducer Calibration System (Type 3629). The sensitivity of the device is 0.24 V/g, and the nonlinearity is 0.29% over the range of 0–1 g.

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