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 700 psi and temperatures up to 574degC are demonstrated. An instrumentation amplifier is used to convert capacitance into voltage for measurements up to 300degC; beyond 300degC, 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.