High temperature piezoresistive β-SiC-on-SOI pressure sensor with on chip SiC thermistor

This paper reports about a piezoresistive β-SiC-on-silicon on insulator (SOI) pressure sensor with an on chip polycrystalline SiC thermistor for high operating temperatures. The β-SiC film was characterized by TEM-analysis, X-ray diffraction and Hall measurements. The investigations show a good single crystal quality of the β-SiC film and a reliable electrical isolation by the buried oxide layer from the substrate at temperatures up to 673 K. The fabricated pressure sensor chip was tested in the temperature range between room temperature and 573 K. The sensitivity at room temperature is S=2.0 mV V−1 bar−1. The temperature coefficient of the sensitivity (TCS) between room temperature and 573 K is TCS=−0.16 %K−1. The temperature coefficient of the resistivity (TCR) of the polycrystalline SiC thermistor is TCR=−0.17 %K−1.