Device and method for detecting a substance using a thin film resonator (FBAR) having an insulating layer

摘要

A device for detecting at least one substance of a fluid, has a piezoacoustic thin film resonator with a piezoelectric layer on which electrode layers are arranged, and an adsorption surface for adsorbing the fluid substance, wherein the piezoelectric and electrode layers and the adsorption surface are designed and arranged on each other such 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 frequency fR which depends on an amount of the substance adsorbed on the adsorption surface because of an excitation alternating field coupled into the piezoelectric layer. An electrical insulating layer is arranged directly on a side of one of the electrode layers facing away from the piezoelectric layer. Particularly advantageous is the combination of an aluminum electrode layer and a silicon dioxide insulating layer.

主权项

1. A device for detecting at least one substance of a fluid, comprising a piezoacoustic thin film resonator comprising:
at least one piezoelectric layer, a first electrode layer arranged on a first side of the piezoelectric layer, the first electrode layer having a side facing away from the piezoelectric layer, at least one second electrode layer arranged on a second side of the piezoelectric layer, and an electrical insulating layer arranged on the side of the first electrode layer facing away from the piezoelectric layer, the electrical insulating layer completely covering both the first and second electrode layers such that the fluid is completely prevented from contacting the first and second electrode layers, at least one adsorption surface for adsorbing the substance of the fluid, the at least one adsorption surface being physically separated from the first electrode layer by the electrical insulating layer, wherein the piezoelectric layer, the first and second electrode layers and the adsorption surface are designed and arranged relative to one another such that:
an excitation alternating field is coupled into the piezoelectric layer by electrically activating the first and second electrode layers,the thin film resonator is excited to a resonance oscillation at a resonance frequency fR because of an excitation alternating field coupled into the piezoelectric layer, andthe resonance frequency fR depends on an amount of the substance adsorbed on the adsorption surface.