Characterization of Poly-SiC Pressure Sensors for High Temperature and High Pressure Applications

Abstract:

We report two improvements of our all-silicon carbide (SiC) micromachined capacitive diaphragm-based pressure sensors: Ti/TaSi2/Pt contact metallization to enhance temperature cycling durability and a 0.5 μm-thin sensing gap to further improve sensor sensitivity. Three sensors with 0.5 μm and 1.5 μm sensing gaps were packaged individually in high temperature ceramic packages and characterized to designed (static) pressures of 2.1 MPa (300 psi), 3.4 MPa (500psi) and 6.9 MPa (1000 psi) up to 550°C. For the 3.4 MPa range sensor (0.5 μm gap, 70 μm diaphragm radius), a sensitivity of 0.06 fF/Pa and a nonlinearity of 2.0% was obtained at 550°C in contact mode operation. In comparison, the 2.1 MPa range sensor (1.5 μm gap, 95 μm diaphragm radius) demonstrated a sensitivity of 0.07 fF/Pa and a nonlinearity of 4.6% at 550°C in contact mode operation. The 6.9 MPa range sensor (1.5 μm gap, 70 μm diaphragm radius) demonstrated a sensitivity of 0.03 fF/Pa and a nonlinearity of 4.0% at 500°C, also in contact mode.

• Periodical: Materials Science Forum (Volumes 717-720)
• Pages: 1211-1214
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.717-720.1211
• Online since: May 2012
• Authors: Sheng Jin, Srihari Rajgopal, Mehran Mehregany
• Keywords: Capacitive, High-Pressure, High-Temperature, Pressure Sensor, Silicon Carbide (SiC)

References

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[2] S. Jin, X.A. Fu, M. Mehregany, Ohmic contacts on n-type polycrystalline silicon carbide with Ti/TaSi2/Pt, Solid-State Sensors, Actuators and Microsystems Conference, (2009) 1083-1086.

DOI: 10.1109/sensor.2009.5285947