Squeeze film absolute pressure sensors with sub-millipascal sensitivity

Abstract

We report on the realization of ultrasensitive absolute pressure sensors based on silicon nitride membrane sandwiches. These sandwiches consist in a pair of highly-pretensioned, ultrathin (50 nm), large area (0.25 mm2) films, suspended parallel to each other and forming an ultrashort (500 nm), open cavity. The compression of a gas in this cavity leads to a strong squeeze film force, resulting in an increase in the membrane mechanical resonance frequencies which is directly proportional to the absolute gas pressure. These sandwiches show a record high responsitivity of >300 Hz/Pa in terms of squeeze film-induced frequency shift, which, combined with high quality factor mechanical resonances (Q>10^6), allows for bringing the sensitivity of absolute squeeze film pressure sensors down to the sub-millipascal level.

References in corpus (5)

• Optical spatial differentiation with suspended subwavelength gratings
• Effects of pressure on suspended micromechanical membrane arrays
• Squeeze-film effect on atomically thin resonators in the high-pressure limit
• Stress-controlled frequency tuning and parametric amplification of the vibrations of coupled nanomembranes
• Mechanical investigations of free-standing SiN membranes patterned with one-dimensional photonic crystal structures

Cited by in corpus (5)

• Accurate, precise pressure sensing with tethered optomechanics
• Highly reflective and high-$Q$ thin resonant subwavelength gratings
• Dynamical measurement of saturation vapor pressures below and above room temperature
• Single-run determination of the saturation vapor pressure and enthalpy of vaporization/sublimation of a substance undergoing successive solid-solid and solid-liquid phase transitions: the case of $N$-methyl acetamide
• Optical microcavity with a pair of suspended resonant mirrors