Capacitive pressure sensors based on microstructured polymer-derived SiCN ceramics for high-temperature applications

Traditional silicon-based pressure sensors cannot meet demand of pressure information acquisition in high-temperature extreme environments due to their low sensitivity, limited detection temperature and complex processing. Herein, a capacitive pressure sensor is fabricated using polymer-derived SiCN ceramics with convex microstructures via a sample replication strategy. Its performance is measured at different pressures (0-800 kPa) from room temperature to 500 °C. The results show that the SiCN ceramic capacitive pressure sensor exhibits low hysteresis, good non-linearity of 0.26 %, outstanding repeatability and high sensitivity of 0.197 pF/MPa under room temperature. When the test temperature reaches 500 °C, the performance of the prepared capacitive pressure sensor has no degradation, keeping competent sensitivity of 0.214 pF/MPa and nonlinear error of 0.24 %. Therefore, benefitting from the preeminent high-temperature properties, e.g., excellent oxidation/corrosion resistance and thermal stability, SiCN ceramics capacitive pressure sensors have great potential in the application of high-temperature and harsh environments.