High-temperature pressure and temperature multi-function sensors

High-temperature pressure and temperature multi-function sensors have been fabricated using polysilicon as piezoresistor and silver resistors as thermometer. The polysilicon SOI structure is able to operate at high temperature. Over the range of room temperature to 350/spl deg/C, the pressure and temperature properties of the sensors have been measured. For 0.6 Mpa full scale pressure, the typical pressure sensitivity is 4.42 mV/V/MPa at 27/spl deg/C and 3.32 mV/V/MPa at 352/spl deg/C, with temperature coefficient of -0.077%/spl deg/C/sup -1/. The silver thermometer has the temperature coefficient of +0.242%/spl deg/C/sup -1/, with good linearity.