A novel temperature compensated piezoresistive pressure sensor

摘要

The main drawback of current piezoresistive pressure sensors is the drop of output voltage with increase in the operating temperature which severely reduces the measurement accuracy. This paper presents a novel passive technique for temperature compensation of silicon piezoresistive pressure sensors. The built-in compensation technique eliminates the need for expensive and time consuming calibration process required for each sensor inside a fabricated batch. In this technique, extra polysilicon resistors with negative Temperature Coefficient of Resistivity (TCR) are employed for compensation purpose. Through applying this technique, Temperature Coefficient of Sensitivity (TCS) of the conventional non-compensated sensor was reduced to zero. Analytically derived equations and verified Finite Element Model considering mechanical, piezoresistive and electrical characteristics of the sensor are adapted to analyze the behavior of the sensor. The implementation of the introduced technique is compatible with conventional MEMS devices fabrication process. The compensated sensor is advantageous for pressure measurement in harsh environments with temperature variations. (C) 2014 Elsevier Ltd. All rights reserved.