A MEMS friction vacuum gauge suitable for high temperature environment

This work describes a new vacuum gauge consisting of a micromechanical silicon torsion resonator with electrostatic actuation. The damping by the rarefied gas in between resonator plate and a nearby wall is used as a measure for the pressure. Capacitive detection of the damped oscillation and signal analysis by digital signal processing give the damping and the information about vacuum pressure as well. The advantages to actual vacuum gauges are significant smaller dimensions. The sensitivity above 1 mbar, which is a limit for conventional friction gauges, is conspicuously higher. The sensor has a measurement range of nearly eight decades from 10−5 mbar to ambient pressure and works up to temperatures of 350 °C without any restrictions.