The hot-filament vacuum gauge is a traditional gauge for the vacuum measurement below 10-1Pa. It consists of the cathode, grid and anode. The cathode is used to emit the electron to collide with a gaseous molecular to form a pair of ion and electron. The number of these ions is proportional to the gaseous molecule density and the gas pressure. Unlike the traditional gauge with the large dimension, this paper develops a CMOS-compatible hot-filament vacuum gauge. With it, the vacuum gauge and its control circuit can be fabricated monolithically on a chip which will decrease the noise and be easy to use. Besides that, the optimal heating current for the cathode is also considered in this paper. The electro-thermal modeling using COMSOL software is introduced to calculate the heating current for cathode. The results show that for 200μm×5μm×0.2μm tungsten resistor, 200mA current is needed to heat the tungsten resistor to 1800°C to emit the electron.
Electrons on a straight path: A novel ionisation vacuum gauge suitable as reference standard
