Fabrication and Characterization of a Polycrystalline 3C-SiC Piezoresistive Micro-pressure Sensor

This paper describes polycrystalline (poly) 3C-SiC piezoresistive micro-pressure sensors for extreme environment applications prepared with a combination crystal growth technology using chemical vapor deposition (CVD) and micromachining techniques. The device was designed using bulk micromachining tinder a 1. x 1 mm(2) diaphragm and a Si membrane with a thickness of 20 mu m. The pressure sensitivities of the fabricated pressure sensors were 0.1 mV/V.bar. The nonlinearity of the devices was +/- 0.44%.FS, and the hysteresis was 0.61%.FS. The temperature characteristics of the temperature coefficient of sensitivity (TCS), the temperature coefficient of resistance (TOR.), and the temperature coefficient of the gauge factor (TCGF) were also evaluated. The TCS of the pressure sensors was -1,867 ppm/degrees C, the TCR was -792 ppm/degrees C, and the TCGF to 5 bars was -1,042 ppm/degrees C, from 25 to 400 degrees C.