Author(s)

C. Malhaire¹, A. Danescu², V. Lysenko¹, A. Sabac¹

¹Université de Lyon, Institut de Nanotechnologies de Lyon INL-UMR 5270, CNRS, INSA Lyon, Villeurbanne, France.
²Université de Lyon, Institut de Nanotechnologies de Lyon INL-UMR 5270, CNRS, école Centrale de Lyon, écully, France.

This study focuses on the mechanical response of silicon on porous silicon bilayer cantilevers ended with a seismic mass. The porous silicon is intended to provide an alternative to decrease the cantilever stiffness for low-frequency MEMS applications. The first eigenfrequency of the cantilever is obtained using static deflection obtained under classical Euler-Bernoulli assumptions and Rayleigh method. In order to estimate the errors due to small-strain approximation and Euler-Bernoulli theory, the analytical results were validated through 3D finite element simulations for different cantilever geometries and porosities. Both bulk silicon and silicon on porous silicon bilayer cantilevers ended with a seismic mass were fabricated and we measured the first eigenfrequency (f₀) and quality factor (Q) by using a laser Doppler vibrometer. In agreement with the theoretical predictions we found that, when compared to bulk silicon cantilevers, the first eigenfrequency of a bilayer cantilever containing 6% porous silicon (at 50% porosity) on 94% bulk silicon is lowered by 5%, from (5447 ± 120) Hz to ≈ 5198 Hz. This decrease is also accompanied by a reduction of the quality factor by two.

Porous Silicon, Cantilever, Resonator

Malhaire, C. , Danescu, A. , Lysenko, V. and Sabac, A. (2018) Porous Silicon as Soft Material in Low-Frequency MEMS (MicroElectro-Mechanical Systems) Resonators. World Journal of Mechanics, 8, 431-443. doi: 10.4236/wjm.2018.811031.