DEVICE AND METHOD FOR DETECTING A SUBSTANCE USING A THIN FILM RESONATOR (FBAR) HAVING AN INSULATING LAYER

摘要

The invention relates to a device for detecting at least one substance of a fluid, comprising a piezoacoustic thin film resonator having at least one piezoelectric layer, an electrode layer arranged on the piezoelectric layer, at least one further electrode layer arranged on the piezoelectric layer, and at least one adsorption surface for adsorbing the substance of the fluid, wherein the piezoelectric layer, the electrode layers, and the adsorption surface are designed and arranged on each other in such a way that by electrically activating the electrode layers, an excitation alternating field can be coupled into the piezoelectric layer, the thin film resonator can be excited to a resonance oscillation at a resonance frequency fR because of an excitation alternating field coupled into the piezoelectric layer, and the resonance frequency fR depends on an amount of the substance adsorbed on the adsorption surface. The device is characterized in that at least one electrical insulating layer for electrically insulating the electrode layer is arranged directly on a side of at least one of the electrode layers facing away from the piezoelectric layer. Particularly advantageous is the combination of an electrode layer made of aluminum and an insulating layer made of silicon dioxide. A relatively high mass sensitivity thus results. The device is used particularly as a biosensor for detecting and analyzing biomolecules.