Research on Temperature Zero Drift of SiC Piezoresistive Pressure Sensor Based on Asymmetric Wheatstone Bridge

Temperature drift restricts the measurement accuracy and application fields of high temperature pressure sensors. In this work, a theoretical model of temperature characteristics in SiC piezoresistive pressure sensor was developed to analyze the influence factors of temperature zero drift, including temperature dependence of resistivity and thermal expansion deformation of diaphragm. Then the effect of various size combinations of piezoresistors on the zero-point output of pressure sensors was investigated through the finite element method and an asymmetric Wheatstone bridge was proposed to effectively compensate for temperature zero drift. The size of transverse piezoresistor should be larger than that of longitudinal piezoresistor when the resistances are equal. Finally, the validity of the asymmetric Wheatstone bridge in sensor model with manufacturing errors was further evaluated. The above research results are significant for the structural design and performance optimization of SiC piezoresistive pressure sensors.