Silicon laterally resonant microcantilevers for absolute pressure measurement with integrated actuation and readout

This work is focused on the design, fabrication, and characterization of silicon laterally resonant microcantilevers for measuring absolute pressure. The authors have demonstrated the integration of resonance electrostatic actuation and capacitive readout with a microstructure based on a couple of electrodes and an external amplifier. The microcantilevers have been fabricated with a standard silicon on insulator micromachining process. The characterization method is based on measuring the current at the third harmonic of the excitation frequency flowing through the time-varying cantilever-based capacitor. The variation in resonance response of microcantilevers has been investigated as a function of pressure 10-2-105 Pa, both in terms of resonance frequency and quality factor. Theoretical models and experimental data show very good agreement. The microstructure behavior demonstrates the feasibility of an absolute pressure sensor working over a six-decade range with integrated electrical actuation and readout.