A Micromachined Quartz and Steel Pressure Sensor Operating Upto 1000°C and 2000 Torr

This paper describes microdischarge-based pressure sensors which operate by measuring the change, with pressure, in the spatial current distribution of pulsed DC microdischarges. These devices are well-suited for high temperature operation because of the inherently high temperatures of the ions and electrons in the microdischarges, and are designed to allow for unequal expansion of electrodes and substrate during high temperature operation. These sensors use three-dimensional arrays of horizontal bulk metal electrodes embedded in quartz substrates with electrode diameters of 1-2 mm and 50-100 mum inter-electrode spacing. The sensors were operated in nitrogen over a range of 10-2,000 Torr, at temperatures as high as 1,000degC. The maximum measured sensitivity was 5,420 ppm/Torr at the low end of the dynamic range and 500 ppm/Torr at the high end, while the temperature coefficient of sensitivity ranged from -925 ppm/K to -550 ppm/K.