α(6H)-SiC pressure sensors for high temperature applications

Abstract

A batch-microfabricated 6H-SiC diaphragm-based piezoresistive pressure sensors with working temperature range between 80/spl deg/F to 500/spl deg/F had been produced. The net output voltage shows an output voltage of 131.59 mV at full-scale pressure of 1000 psi. The net output voltage response to temperature up to 500/spl deg/F is also presented. The Temperature Coefficient of Resistance (TCR) of the device exhibits a TCR of -3.07%/100/spl deg/F at 180/spl deg/F and eventually becomes a positive value of 4.24%/100/spl deg/F at 500/spl deg/F. The Temperature Coefficient of Gage Factor (TCGF) exhibits negative values of -15%/100/spl deg/F and -10%/100/spl deg/F at 180/spl deg/F and 500/spl deg/F, respectively. The problem of micropipes in 6H-SiC was effectively resolved, making it possible to fabricate thin diaphragms of about 25 /spl mu/m.