Surface-Micromachined Silicon Carbide Pirani Gauges for Harsh Environments

The application of pressure sensors in harsh environments is typically hindered by the stability of the material over long periods of time. This work focuses on the design and fabrication of surface micromachined Pirani gauges which are designed to be compatible with state-ofthe-art Silicon Carbide CMOS technology. Such an integrated platform would boost harsh environment compatibility while reducing the required packaging complexity. An analytical model was derived describing the design variables of the Pirani gauges followed by Finite Element Analysis. The Pirani gauges were fabricated in a CMOS compatible cleanroom with a process employing only three masks, thus suitable for mass production. The SiC-based Pirani gauge is far more competitive than the traditionalSi-based Pirani gauge in terms of endurancein high-temperatureenvironments. From25 degrees C to 650 degrees C, the gauge shows a reproducible response to pressure changes and has a maximum sensitivity of 17.63 Omega/Pa at room temperature, and of 1.23 Omega/Pa at 650 degrees C. Additionally, some of the gauges were demonstrated to operate at temperatures up to 750 degrees C.

Automated summary

This study focuses on the design and fabrication of surface micromachined Pirani gauges compatible with state-of-the-art Silicon Carbide CMOS technology, which improves harsh environment adaptability and reduces packaging complexity. The SiC-based Pirani gauges demonstrate better endurance in high-temperature environments compared to traditional Si-based gauges.