Mechanical Diaphragm Structure Design of a MEMS-Based Piezoresistive Pressure Sensor for Sensitivity and Linearity Enhancement

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

Enhancing Performance of a MEMS-Based Piezoresistive Pressure Sensor by Groove: Investigation of Groove Design Using Finite Element Method

The optimal groove design of a MEMS piezoresistive pressure sensor for ultra-low pressure measurement is proposed in this work. Two designs of the local groove and one design of the annular groove are investigated. The sensitivity and linearity of the sensor are investigated due to the variations of two dimensionless geometric parameters of these grooves. The finite element method is used to determine the stress and deflection of the diaphragm in order to find the sensor performances. The sensor performances can be enhanced by creating the annular or local groove on the diaphragm with the optimal dimensionless groove depth and length. In contrast, the performances are diminished when the local groove is created on the beam at the piezoresistor. The sensitivity can be increased by increasing the dimensionless groove length and depth. However, to maintain low nonlinearity error, the annular and local grooves should be created on the top of the diaphragm. With the optimal designs of annular and local grooves, the net volume of the annular groove is four times greater than that of the local groove. Finally, the functional forms of the stress and deflection of the diaphragm are constructed for both annular and local groove cases