A silicon carbide capacitive pressure sensor for high temperature and harsh environment applications

We report the first all-Silicon Carbide (SiC) capacitive pressure sensor - incorporating a SiC diaphragm on a SiC substrate - to measure pressure in high temperature and harsh environments, for example, propulsion and power systems. Measurements of pressures up to 700psi and temperatures up to 574 degrees C are demonstrated. An instrumentation amplifier is used to convert capacitance into voltage for measurements up to 300 degrees C; beyond 300 degrees C, the capacitance is measured directly from an array of identical sensor elements using a LCZ meter. Even after high temperature soaking, the packaged sensors show stable operation after several tens of thermal and pressure cycles.