MEMS type ionization vacuum sensor

The paper presents the first MEMS type ionization vacuum sensor corresponding to the classical gauges with cold cathodes. In contrast to the other MEMS sensors, it works both in medium and high vacuum. It covers a pressure range from 20 down to 10−4 Pa. The sensor is made of silicon and glass substrates by the use of microengineering techniques. The overall dimensions of the sensor are 20 × 12 × 10 mm3. It operates on the principle of ionization of gases in an electric discharge, similarly to the Penning gauge. The value of the discharge current is a measure of pressure. The sensor can also be used for residual gas composition analysis in pressure range from 1000 Pa to 10−1 Pa. The composition of gas species is determined on the basis of spectra of the glowing gases, recorded by a miniature fiber spectrometer. Properties of the sensor: relations between discharge current, pressure, and power supply conditions, as well as characteristic spectral lines have been measured in a reference vacuum chamber for air and several gases.