Acoustic resonator performance enhancement using selective metal etch
View Patent ↗An acoustic resonator comprises: a substrate; a first electrode adjacent the substrate; a layer of piezoelectric material adjacent the first electrode; a second electrode adjacent the layer of piezoelectric material; and a passivation layer adjacent the layer of piezoelectric material. The passivation layer includes a recessed feature. Fill material is provided in the recessed feature of the passivation layer.
1. An acoustic resonator comprising:
a substrate;
a first electrode adjacent the substrate;
a layer of piezoelectric material adjacent the first electrode;
a second electrode adjacent the layer of piezoelectric material;
a passivation layer adjacent the second electrode, wherein the passivation layer includes a recessed feature; and
fill material in the recessed feature of the passivation layer, wherein the fill material is not electrically connected to the acoustic resonator.
2. The acoustic resonator of claim 1 wherein the second electrode comprises a material that is the same as the fill material in the recessed feature.
3. The acoustic resonator of claim 1 wherein the fill material is a material selected from the group comprising dielectrics, metals, piezoelectrics, Mo, Pt, Al, Cu, W, Au, Ag, polyimide, BCB (benzocyclobutene), SiO 2 , Si 3 N 4 , AlN, ZnO, LiNbO 3 , PZT, LiTaO 3 , or Al 2 O 3 .
4. The acoustic resonator of claim 1 wherein the recessed feature has a depth in the passivation layer that is on the order of ten to thousands of angstroms and a width on the order of fractions of a micron to microns.
5. An acoustic resonator comprising:
a substrate;
a first electrode adjacent the substrate;
a layer of piezoelectric material adjacent the first electrode;
a second electrode adjacent the layer of piezoelectric material;
a passivation layer adjacent the second electrode, wherein the passivation layer includes a recessed feature; and
fill material in the recessed feature of the passivation layer, wherein the recessed feature extends around a substantial portion of the perimeter of the passivation layer.
6. The acoustic resonator of claim 5 , wherein the second electrode comprises a material that is the same as the fill material in the recessed feature.
7. The acoustic resonator of claim 5 , wherein the fill material is a material selected from the group comprising dielectrics, metals, piezoelectrics, Mo, Pt, Al, Cu, W, Au, Ag, polyimide, BCB (benzocyclobutene), SiO 2 , Si 3 N 4 , AlN, ZnO, LiNbO 3 , PZT, LiTaO 3 , or Al 2 O 3 .
8. The acoustic resonator of claim 5 , wherein the recessed feature has a depth in the passivation layer that is on the order of ten to thousands of angstroms and a width on the order of fractions of a micron to microns.