Silicon made resonant microcantilever: Dependence of the chemical sensing performances on the sensitive coating thickness

Abstract

A gas sensor based on the use of a resonating microcantilever has been realized by using a polymer sensitive coating. From the theoretical study of the microcantilever sensitivity, it has been deduced that the sensitivity is enhanced when the resonant frequency or the sensitive coating thickness are increased. The sensitive coating thickness influence has then been verified experimentally by using PEUT (polyetherurethane) as sensitive coating for ethanol detection. From these measurements, some drawbacks are shown: the coating thickness increase leads to a sensor response time increase and a frequency noise increase which worsens the limit of detection. Conclusions are then made about the sensitive coating optimization depending on application constraint considerations.

Bimaterial Microcantilevers as a Hybrid Sensing Platform

“…Various methods such as drop casting, [135][136][137][138] spin coating, [139,140] inkjet printing, [133] spray coating, [141,142] capillary painting, [143] plasma polymerization, [144] in situ polymerization, [145][146][147][148] grafting to via SAM functionalization, [149] and matrix assisted pulsed laser evaporation (MAPLE) [150] have been adapted for modifying MCs.…”

“…Even more recently, Lochon et al have shown that the sensitivity (measured in terms of a frequency shift) of poly(etherurethane) coated MCs increases linearly with thickness of the coatings (1-20 lm). [142] However, the thermal noise of the MCs also increased significantly for MCs with the thicker coating making the detection limit to stay constant or even worsening with the increase in the coating thickness. Moreover, they have also shown that the increase in the coating thickness causes an increase in the response time, a highly undesirable output.…”

Biomimetic cross-reactive sensor arrays: prospects in biodiagnostics

“…Microcantilevers, such as those on an Atomic Force Microscope, are fabricated as a bilayer system, typically composed of silicon or silicon nitride and a chemically selective layer. 23,26,30–32 These two layers have a difference in thermal expansion, which causes the cantilever to oscillate at a specific fundamental frequency, calculated using Newton's second equation of motion 30 :…”

Characterization of the gas sensors based on polymer-coated resonant microcantilevers for the detection of volatile organic compounds

“…Polymers can be easily deposited and structured using spray coating [13,14], drop coating [15,16] or spin coating [17] methods. A wide range of polymers have been employed in microcantilever sensors for VOCs detection [18][19][20][21][22][23][24][25][26][27][28]. Because polymer coatings are not uniquely selective to one analyte vapor, it is typical that different polymers are used in microcantilever array for MCM analyses [18][19][20][21][22][23][24].…”