Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)
O 17.54: Poster
Montag, 26. März 2007, 17:30–20:30, Poster C
Miniaturised Columnar Sensors for Ultrasensitive Mass Detection — •Jenny Kehrbusch1,2, Matthias Hullin1, and Egbert Oesterschulze1,2 — 1Physics and Technology of Nanostructures, University of Kaiserslautern, D-67663 Kaiserslautern, Germany — 2Nano+Bio Center, University of Kaiserslautern, Germany
Cantilever based microsensors are commonly used as ultrasensitive mechanical balances operating in gases and liquids. They are sensitive to changes of the viscosity of the surrounding fluid, chemically induced surface effects, and mass loading of their surface. So far their sensitivity with respect to mass loading in fluidic media is limited due to the strong viscous damping of the vibrating cantilever. The quality factor in liquids is by orders of magnitude smaller compared to gases even with active stimulation. Furthermore, the huge dimension of conventional cantilevers hinders to achieve high quality factors.
To overcome this limitation an improved concept of a columnar strongly miniaturized sensor is introduced. This sensor is oscillating in air where only the top surface is immersed in the liquid analyte. Thus both the quality factor and the signal-to-noise-ratio are improved. The new design combines additional advantages. Instead of an intricate double-sided fabrication process, simple single sided few steps manufacturing applying high aspect ratio deep plasma etching offers the possibility of further miniaturisation. Reduction of the geometrical dimensions implies higher resonance frequencies and thus an improved sensitivity per area. This is an important issue for the application of miniaturized balances, e.g. single-cell detection in liquid media.