Sapphire-based capacitance diaphragm gauge for high temperature applications

The packaging technologies for an entirely sapphire-based capacitive pressure sensor chip have been developed. This sensor, capable of withstanding 200°C of self-heating temperature, covers a dynamic absolute pressure range from 0 to 133 Pa, 0 to 1,333 Pa, or 0 to 13 kPa. By adopting interlayer-less bonding methods, the packaging technology features low mechanical stress from the exterior metal body to the sensor chip and high corrosion resistance. The pressure performance of this packaged sensor corresponds well to the calculated values. In respect to reliability, zero drifts after one hundred 100-200°C heat cycles and after one thousand 300 kPa overpressure cycles are both less than 0.1 %FS.