engleski

Tunable micro-electro-mechanical system resonators electrothermally actuated and piezoelectrically sensed

Micro-electro-mechanical system (MEMS) resonators have been used in wide range of applications, such as oscillators, filters, gyroscopes, accelerometers and sensors. One of the main problems affecting MEMS resonators consists of resonant frequency shifts arising from changes in the ambient conditions (variations of temperature and pressure) or fabrication process uncertainties (variations of geometrical dimensions and material properties, residual stress). Therefore, capability of active frequency tuning that is repeatable and reversible is a vital feature for MEMS resonators to work effectively on a specific frequency. Electrothermal actuation is an emerging transduction technique that brings advantages such as simple fabrication process, low actuation voltages, impedance matching and wide frequency tuning range that can be obtained by applying low DC bias voltages. The use of piezoelectric transduction for electrical sensing allows active generation of electrical potential in response to an applied mechanical stress, and thus obviating the need of external bias voltage source. Electrothermally actuated and piezoelectrically sensed MEMS resonators have been fabricated with three different resonant structures: single-clamped beam, double-clamped beam and diaphragm. Electrical characterization of the devices has been performed by measuring the two-port transmission frequency response. Details on devices’ design, materials, fabrication process and testing procedure have beeen presented.

MEMS, Resonators, Electrothermal actuation, Piezoelectric sensing, Silicon-Carbide

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