AlN Sputter-Deposited Silicon Cantilever Resonators for Mass Sensing Fabricated Using ICP-DRIE

Conference: Mikro-Nano-Integration - 2. GMM-Workshops
03/03/2010 - 03/04/2010 at Erfurt, Germany

Proceedings: Mikro-Nano-Integration

Pages: 4Language: englishTyp: PDF

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Sökmen, Ü.; Waag, A.; Peiner, E. (Institute of Semiconductor Technology, Braunschweig University of Technology, Hans-Sommer-Str. 66, 38106 Braunschweig, Germany)
Ababneh, A.; Seidel, H. (Chair of Micromechanics, Microfluidic/Microactuators, Saarland University, Uni Campus, Gebäude A5.1, 66123, Saarbrücken, Germany)
Schmid, U. (Department for Microsystems Technology, Institute of Sensor and Actuator Systems, Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria)

We report on the fabrication and evaluation of micromachined resonators for mass sensing applications. These resonators are based on a silicon cantilever excited with a sputter-deposited aluminium nitride (AlN) thin film actuator. These devices can be used most beneficially for the detection of nano-sized particles in air as they are regarded as growing threat on the human health. Although the size of the nanoparticles can be determined, it is not easy to measure their weights. Nowadays it is possible to fabricate microbalances by using micromachining techniques in order to weigh very low masses. This machining can easily be done by using the ICP-DRIE cryogenic dry etching process. A resonator consisting of a silicon cantilever can be used as a very sensitive balance. The actuation of these cantilevers can be done by using a piezoelectric layer, e.g. AlN thin film, sandwiched between two electrodes. The fabricated resonator revealed a resonance frequency of 1.67931 kHz and a quality factor of 155. A resonance frequency shift was observed by loading mass, i.e. evaporated aluminium on the cantilever, of 200 ng.