Vincent Agache

Experimental Study of Energy Dissipation in High Quality Factor Hollow Square Plate MEMS Resonators for Liquid Mass Sensing

We report on a capacitively transduced, Lamé-mode resonator for real-time mass sensing in liquid. The resonators are fabricated in silicon, presenting a square plate geometry, and incorporate an integrated fluidic channel diagonally crossing the 50 μm wide plate. Varying shapes of the buried fluidic channels (rectangular and ellipsoidal) are studied, resulting in mechanical resonance frequencies between 70 and 78 MHz. Volumes of those nanochannels range between 223 and 833 fL. For fluid-filled rectangular channels, quality factors demonstrate increasing values up to 4300 (compared with 3200 in air), when the resonance frequency × quality factor product exceeds 300 GHz. An extensive study has been carried out with the rectangular channels, showing downward frequency shifts proportional to the liquid mass, as compared with dry devices. Experimental mass responsivities for all tested devices approached 1 kHz.pg-1. We examined different sources of dissipation, taking place in our structures, through qualitative analysis to explain the quality factor variations between dry and wet devices. We particularly focused on flow conditions, the vibration amplitude, the channel design and position relative to the resonator anchor, as well as the variation of acoustic energy dissipation within the embedded-channel cavities.

Suspended nanochannel in MEMS plate resonator for mass sensing in liquid

A mass sensor innovative concept is presented here, based on a hollow plate MEMS resonator (Fig. 1). This approach consists in flowing a solution through the embedded nanochannel, while the plate resonator is actuated by electrostatic coupling in dry environment. The experimental results have shown a clear relationship between measured shift of the resonant frequency and the sample solution density. Additionally, depending on the nanochannel design and the solution properties, the results showed the quality factor (Q Factor) maintaining its level and even substantial improvement in some cases, leading to a striking resonant frequency × Q factor product as high as 3.4 × 1011 measured for liquid phase.

Hollow Lamé mode MEMS mass sensors with 10 ppb-range stability for particles counting and weighing in fluid

This paper reports hollow MEMS plate oscillators for mass sensing in liquid with an extracted mass resolution of 7 femtograms. The sensors performances show a one-fold improvement compared to previous alike structures - 10,000-range Q factor and ppb-range frequency stability. These devices are connected through a customized plug and play test platform and do not need to work in a vacuum-sealed package. These performances, reached in ambient conditions whether the embedded channel is filled with air or water, make the devices potentially amenable to individual particles metrology from a few 10 nm up to the μm diameter range.

Hollow MEMS mass sensors for real-time particles weighing and sizing from a few 10 nm to the μm scale

This paper reports hollow MEMS plate oscillators for mass sensing in liquid with an extracted mass resolution of 4 femtograms. The sensors performances - 10,000-range Q factor and ppb-range frequency stability - make them amenable to individual particles metrology from a few 10 nm up to the micrometer diameter range. These devices are operating in air, connected through a customized plug and play test platform and do not need to work in a vacuum-sealed package.