Development of a Novel Two Axis Piezoresistive Micro Accelerometer Based on Silicon

This paper describes the design, simulation, fabrication and test results of a novel MEMS two axis accelerometer, which is based on piezoresistive detection. This kind of sensor consists of four vertical cantilever beams with attached plastic cylinder in the center of the structure. A simplified analytical model is established to describe the accelerometer’s mechanical behaviour. Finite element modelling is also conducted to verify the analytical model and evaluate the performance of the micro accelerometer. The fabrication of the accelerometer is completed by means of the silicon-oninsulator (SOI) wafer with MEMS technology as well as plastic molding processing. By locating the piezoresistors logically formed the Wheatstone bridge; this sensor can detect two components of acceleration simultaneously. The experiments on sensitivity and frequency response are performed by using a vibrating table, and the results are presented and compared with the theoretical values. The experimental results show that the X and Y axis sensitivities of the micro accelerometer are 1.1177 mv/g and 1.0531 mv/g, respectively. The frequency response gives a straight and smooth line and the measured resonance frequency is 713.2 Hz. Comparison of the results obtained from the experiments, analytical model and finite element simulation shows good agreement.