A Novel Piezoresistive Accelerometer with SPBs to Improve the Tradeoff between the Sensitivity and the Resonant Frequency

Abstract

For improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers, the dependency between the stress of the piezoresistor and the displacement of the structure is taken into consideration in this paper. In order to weaken the dependency, a novel structure with suspended piezoresistive beams (SPBs) is designed, and a theoretical model is established for calculating the location of SPBs, the stress of SPBs and the resonant frequency of the whole structure. Finite element method (FEM) simulations, comparative simulations and experiments are carried out to verify the good agreement with the theoretical model. It is demonstrated that increasing the sensitivity greatly without sacrificing the resonant frequency is possible in the piezoresistive accelerometer design. Therefore, the proposed structure with SPBs is potentially a novel option for improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers.

Thermal-Performance Instability in Piezoresistive Sensors: Inducement and Improvement

“…Though the stress in oxide film can be compensated by LPCVD nitride film, completely elimination of wafer bow still cannot be achieved. The uncompensated stress may have nearly no effect on a general structure with large dimensions, but still cause an obvious decline in the performance robustness of many devices with thin diaphragms or tiny suspended beams [4,54]. For a diaphragm-based pressure sensor, the residual stress-induced curvature is related to the residual stress by Stoney equation as [55]: $\kappa =\frac{6false(1-{\upsilon }_{d}false){\sigma }_r}{E_d{h}_d^2}$ where υ d , E d and h d are the Poisson’s ratio, elastic modulus and thickness of the diaphragm, respectively; σ r is the residual stress.…”

“…Until now, silicon piezoresistances have been utilized in the detection of various targets, including acceleration [4,5,6], pressure [7,8], micro force/torque [9,10], strain/stress [11,12], flow [13,14], biochemical interaction [15,16], fluid density and viscosity [17,18], surface topography [19], sonar vectors [20], etc.…”

Design of the MEMS Piezoresistive Electronic Heart Sound Sensor

“…It should maximally pick up the heart sound vibration signal and achieve the best performance under the heart sound frequency range condition. However, the sensitivity and the first-order resonant frequency of the MEMS electronic heart sound sensor restrain each other [17]. To solve this problem, a scheme of stress concentration has been proposed.…”

A Mathematical Model of a Piezo-Resistive Eight-Beam Three-Axis Accelerometer with Simulation and Experimental Validation

“…Their shortcoming is the susceptibility to temperature changes. Since they were first developed by Roylance and Angell [ 10 ], many scholars have done a lot of work about piezo-resistive accelerometers [ 11 , 12 , 13 , 14 ].…”