Investigating the advanced characteristics of SiC based piezoresistive pressure sensors

Abstract With the advances in science, the operating performances of machinery and equipment in long-term harsh environment are significantly improved. Hence the capabilities of anti-impact, anti-vibration and high temperature resistance are becoming the labels of distinguished miniature sensors. Of late, due to attractive materials properties silicon carbide (SiC) based sensors are widely used in many aspects of engineering such as aerospace, automobile industry and civil works. However, the theoretical understanding of SiC based sensors under impulsive pressure excitation, wide range of temperature and high-frequency vibration pressure has not been reported in pervious works. In this paper, a mathematical model of multifield coupling concerning SiC based piezoresistive pressure sensors is presented. The influences of temperature on electrical conductivity and piezoresistive coefficient are approximately defined. The static and dynamic output characteristics of SiC based pressure sensors are studied and compared with Si. Furthermore, the hysteresis characteristics and nonlinearity of SiC based pressure sensors are calculated and compared with Si. Finally, output characteristics of SiC based pressure sensors under harmonic pressure excitation are evaluated and compared with Si. Results show that the static sensitivity of SiC is larger than Si and maintains more stable against temperature changes. The maximum hysteresis, hysteresis error and nonlinearity of SiC are much smaller than their counterparts of Si. The dynamic sensitivity of SiC based sensors maintains more stable under various impulsive pressure excitation in comparison with its counterpart of Si based sensors. In addition, the effective frequency threshold and bandwidth of SiC based pressure sensors are much larger than Si based pressure sensors.