Component operating with acoustic waves and method for producing same
The invention concerns a component (B) operating with acoustic waves, in which the reflection and excitation are largely decoupled. For this purpose, a component comprises a dielectric (DL) which is arranged between an electrode finger (EF) and a piezoelectric substrate (PSU) and at least partially overlaps the electrode finger.
1. A component operating with acoustic waves, comprising:
a piezoelectric substrate;
a dielectric;
an electrode finger arranged above the substrate and having an overlap region with the dielectric and a mechanical finger width;
a contact region, in which the electrode finger makes contact with the substrate; and
a further dielectric,
wherein the dielectric is arranged above the substrate and in the overlap region between the substrate and the electrode finger,
wherein the width of the electrode finger defines the mechanical finger width of the electrode finger,
wherein the width of the contact region defines the electrical finger width of the electrode finger, and
wherein the further dielectric is arranged in a partial overlap region between the dielectric and the electrode finger.
2. The component according to claim 1 , wherein the electrode finger has a contact region and the center of the contact region is shifted relative to the center of the electrode finger.
3. The component according to claim 1 , wherein the dielectric constant of the dielectric is less than the dielectric constant of the piezoelectric substrate.
4. The component according to claim 1 , wherein the dielectric comprises SiO 2 , TiN, Al 2 O 3 , Ta 2 O 5 , HfO, HfO 2 , or Si 3 N 4 .
5. The component according to claim 1 , further comprising a multiplicity of electrode fingers each having a mechanical finger width and an electrical finger width different therefrom.
6. The component according to claim 5 , wherein each of the electrode fingers excites acoustic waves at the top side of the substrate.
7. The component according to claim 5 , further comprising a dielectric cover layer arranged above each top side of electrode finger, dielectric and substrate, wherein the totality of the electrode fingers excites guided bulk acoustic waves at the top side of the substrate.
8. A component operating with acoustic waves, comprising:
a piezoelectric substrate;
a dielectric; and
an electrode finger arranged above the substrate and having an overlap region with the dielectric and a mechanical finger width,
wherein the dielectric is arranged above the substrate and in the overlap region between the substrate and the electrode finger,
wherein the width of the electrode finger defines the mechanical finger width of the electrode finger,
wherein at least the dielectric is arranged in a depression at the surface of the piezoelectric substrate, and
wherein the surfaces of the dielectric and of the substrate form a common plane in a contact region in which the electrode finger makes contact with the substrate.
9. The component according to claim 1 , wherein the piezoelectric substrate is a layer applied on a carrier substrate.
10. The component according to claim 1 , comprising two or more layer systems each operating with acoustic waves and arranged one above another.
11. A method for producing a component operating with acoustic waves, comprising the following steps:
providing a piezoelectric substrate;
forming and structuring a dielectric on the top side of the substrate; and
forming and structuring at least one electrode finger such that regions of individual or a plurality or all of the at least one electrode finger make contact with the substrate and other regions of the electrode fingers overlap the dielectrics;
providing a contact region, in which the at least one electrode finger makes contact with the substrate, wherein the width of the contact region defines the at least one electrical finger width of the electrode finger; and
providing a further dielectric, wherein the further dielectric is arranged in a partial overlap region between the dielectric and the at least one electrode finger.