Microelectromechanical systems (MEMS) offer important advantages with respect to standard semiconductor devices such as: low power consumption, high miniaturization and integration with integrated circuits (ICs) [1]. For all these reasons, MEMS have been applied in radars, communication, sensing and other fields [2,3]. In particular, the biological application of MEMS is appealing thanks to the several benefits offered by the MEMS technology, which are: device dimension compatible with the size of the single cell, wide range (pN-μN) of applicable forces, and flexibility in the device design, which allows the study of a variety of cells under the application of different stress [3]. However, in spite of the great potential of the MEMS technology, the reliability of devices is still limited and the exploration of innovative materials and technological processes is still mandatory. In this work, electrostatically-actuated microcantilevers were developed in MEMS technology for biosensing applications. The displacement of the suspended beam is driven by the electrostatic force due to the voltage bias applied between the actuator, deposited below the beam, and the beam itself. There are two operating modes of electrostatic microcantilever-based sensors and biosensors: static and dynamic. In former, the analyte adsorption is detected by the direct measure of the deflection of the cantilever, which is caused by the mass loading on its surface. In later, the cantilever deflection is monitored by measuring the change in oscillating frequency, while the sinusoidal voltage applied to the actuator is kept constant. The capacitive method can be used to monitor the deflection of the microcantilever. This method is based on the principle that when the cantilever deflection takes place, due to the adsorption of the analyte, the capacitance of a plane capacitor is changed. According to this method, here a dielectric layer was deposited on the actuator to form a capacitor, with the actuator and the suspended microcantilever acting as parallel plates (see fig.1).

Microcantilevers in MEMS Technology for Biosensing Applications

Bagolini, Alvise;Iannacci, Jacopo;Adami, Andrea;
2015

Abstract

Microelectromechanical systems (MEMS) offer important advantages with respect to standard semiconductor devices such as: low power consumption, high miniaturization and integration with integrated circuits (ICs) [1]. For all these reasons, MEMS have been applied in radars, communication, sensing and other fields [2,3]. In particular, the biological application of MEMS is appealing thanks to the several benefits offered by the MEMS technology, which are: device dimension compatible with the size of the single cell, wide range (pN-μN) of applicable forces, and flexibility in the device design, which allows the study of a variety of cells under the application of different stress [3]. However, in spite of the great potential of the MEMS technology, the reliability of devices is still limited and the exploration of innovative materials and technological processes is still mandatory. In this work, electrostatically-actuated microcantilevers were developed in MEMS technology for biosensing applications. The displacement of the suspended beam is driven by the electrostatic force due to the voltage bias applied between the actuator, deposited below the beam, and the beam itself. There are two operating modes of electrostatic microcantilever-based sensors and biosensors: static and dynamic. In former, the analyte adsorption is detected by the direct measure of the deflection of the cantilever, which is caused by the mass loading on its surface. In later, the cantilever deflection is monitored by measuring the change in oscillating frequency, while the sinusoidal voltage applied to the actuator is kept constant. The capacitive method can be used to monitor the deflection of the microcantilever. This method is based on the principle that when the cantilever deflection takes place, due to the adsorption of the analyte, the capacitance of a plane capacitor is changed. According to this method, here a dielectric layer was deposited on the actuator to form a capacitor, with the actuator and the suspended microcantilever acting as parallel plates (see fig.1).
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11582/300127
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