Mechanical Diaphragm Structure Design of a MEMS-Based Piezoresistive Pressure Sensor for Sensitivity and Linearity Enhancement
Keywords:MEMS, piezoresistive pressure sensor, finite element method, sensitivity, linearity
An improved design of the micro-electromechanical system (MEMS) piezoresistive pressure sensor with a combination of a petal edge, a beam, a peninsula, three cross beams and a center boss is proposed in this work for an operating range of low pressure in order to improve the sensor performance, i.e. the sensitivity and the linearity. The finite element method (FEM) is utilized to predict the stress and the deflection of the MEMS piezoresistive pressure sensor under the applied pressure of 1-5 kPa. The functional forms of the longitudinal stress, the transverse stress and the deflection are formulated by using the power law and then are used to optimize the geometry of the proposed design. The simulation results show that the proposed design is able to produce the high sensitivity up to 34 mV/kPa with the low nonlinearity of 0.11% full-scale span (FSS). The nonlinearity error is lowered by the proposed design of the peninsula, three cross beams and the center boss. The sensitivity is enhanced by increasing the petal edge width. The sensor performance of the proposed design is also compared to that of the previous design in the literature. The comparison reveals that the proposed design can perform better than the previous one.
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