Electrostatic actuation of thin-film microelectromechanical structures

Abstract

Electrostatically actuated thin-film amorphous silicon microbridge resonators J. Appl. Phys. 97, 094501 (2005); 10.1063/1.1877820 Micromechanics of actuation of ionic polymer-metal compositesMicrobridge and cantilever electrostatic actuators are fabricated using thin film technology and surface micromachining at low temperatures ͑р100°C͒ on glass substrates. Electrostatic actuation is accomplished by applying a voltage, combining a dc component to a low frequency ac component, between the microstructure and an underlying gate counterelectrode. The movement is optically detected by focusing a laser beam on the top of the structure and monitoring the deviation of the reflected light, which is proportional to the electrostatically induced deflection. The absolute value of the deflection is obtained using a calibrated piezoelectric actuator sample holder. The response of the structure is measured with a precision better than 5 Å. The deflection of the microstructures is studied as a function of the magnitude of the electrostatic load, and of the type ͑bridge or cantilever͒ and geometrical dimensions of the structure. The mechanical movement is analyzed using an electromechanical model and mechanical properties, such as the microstructure boundary conditions and the materials' Young's modulus in the microstructures, are extracted. Nonlinear effects characteristic of electrostatic deflection are observed at high magnitude electrostatic loads. In addition, nonlinear effects due to mechanical stiffening of the microstructures are also observed near the pull-in voltage.

Performance of thin film silicon MEMS on flexible plastic substrates

“…The fabrication process is similar to the one described above except that the PR sacrificial layer is patterned directly by lithography. This is the standard fabrication process that is used for amorphous silicon MEMS fabrication [4,12,13], but it cannot be adapted to PET substrates because the photoresist stripper solution used for sacrificial layer removal chemically attacks the PET substrate.…”

Micromechanical properties of amorphous, nanocrystalline and transition phase hot-wire thin-silicon MEMS

“…The Al on top is patterned by wet etching followed by patterning of the silicon thin film by reactive ion etching (RIE) to define the structural layer. In the final step the sacrificial PR is selectively removed using a commercial PR stripping solution, leaving an air-gap $1 lm between the gate and the bridge [6].…”

“…The resulting deflection is monitored in vacuum at a pressure of $10 À6 Torr by means of optical setup, described elsewhere [6]. Fig.…”

Optimal design of electromagnetically actuated MEMS cantilevers

“…There are various electrical technologies for actuation of the cantilever displacement. The application of electrostatic actuation scheme is limited to cantilevers of big dimensions [2]. Moreover, it usually involves electrode biasing with relatively high voltage which is another limitation in MEMS technology.…”