Design and modeling of a silicon nitride beam resonant pressure sensor for temperature compensation

A novel method of temperature compensation for thermally excited silicon nitride beam resonant pressure sensors is described and some numerical modeling results for this scheme are presented. The proposed approach is based on measurement of resonant frequencies for two resonant beams inducing different axial stress under an applied pressure. The applied pressure is then measured by working out the difference of the two resonant frequencies. The frequency drift induced on both beams due to ambient temperature influence will be the same, guaranteeing a temperature independent pressure sensing. The device is fabricated in one piece from single crystal silicon by MEMS technology and silicon-rich SiN beams are released by using porous silicon sacrificial layer technology.