Geometrical considerations for the design of liquid-phase biochemical sensors using a cantilever's fundamental in-plane mode

Luke Beardslee (1) , Fabien Josse (2) , Stephen Heinrich (3) , Isabelle Dufour (4) , Oliver Brand (1)

1 ECE GeorgiaTech - School of Electrical and Computer Engineering - Georgia Insitute of Technology
2 Department of Electrical and Computer Engineering
3 Department of Civil, Construction and Environmental Engineering [Milwaukee]
4 IMS - Laboratoire de l'intégration, du matériau au système

The influence of the beam geometry on the quality factor and resonance frequency of resonant silicon cantilever beams vibrating in their fundamental in-plane flexural mode in water has been investigated. Compared to cantilevers vibrating in their first out-of-plane flexural mode, utilizing the in-plane mode results in reduced damping and reduced mass loading by the surrounding fluid. Quality factors as high as 86 have been measured in water for cantilevers with a 20 μm thick silicon layer. Based on the experimental data, design guidelines are established for beam dimensions that ensure maximal Q-factors and minimal mass loading by the surrounding fluid, thus improving the limit-of-detection of mass-sensitive biochemical sensors. Elementary theory is also presented to help explain the observed trends. Additional discussion focuses on the tradeoffs that exist in designing liquid-phase biochemical sensors using in-plane cantilevers.

Domaines: Micro et nanotechnologies/Microélectronique

Luke Beardslee, Fabien Josse, Stephen Heinrich, Isabelle Dufour, Oliver Brand. Geometrical considerations for the design of liquid-phase biochemical sensors using a cantilever's fundamental in-plane mode. Sensors and Actuators B: Chemical, 2012, 164, pp.7-14. ⟨10.1016/j.snb.2012.01.035⟩. ⟨hal-00663591⟩