ACOUSTIC RESONATOR PERFORMANCE ENHANCEMENT USING SELECTIVE METAL ETCH

• US 20100277257A1
• Filed: 07/19/2010
• Published: 11/04/2010
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies Wireless IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Feng, Hongjun, Fazzio, Ronald S.
• Granted Patent: US 8,188,810 B2
• Time in Patent Office: Days
• US Class Current: 333/187
• CPC Class Codes: H03H 9/02118 of lateral leakage between adjacent resonators
• CPC Class Codes: H03H 9/173 Air-gaps

Abstract

An acoustic resonator that includes a substrate, a first electrode, a layer of piezoelectric material, and a second electrode. The substrate has a first surface and the first electrode is adjacent the first surface of the substrate. The layer of piezoelectric material is adjacent the first electrode. The second electrode is adjacent the layer of piezoelectric material, and the second electrode lies in a first plane and has an edge. The layer of piezoelectric material has a recessed feature adjacent the edge of the second electrode.

Claims

1-18. -18. (canceled)

19. 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 layer of piezoelectric material, wherein the passivation layer includes a recessed feature; and

fill material in the recessed feature of the passivation layer.

20. The acoustic resonator of claim 19 wherein second electrode comprises a material that is the same as the fill material in the recessed feature.

21. The acoustic resonator of claim 19 wherein the fill material is a material selected from the group comprising dielectrics, metals, piezoelectrics, Mo, Pt, Al, Cu, W, Au, Ag, polyimide, BCB, SiO₂, Si₃N₄, AlN, ZnO, LiNbO₃, PZT, LiTaO₃, or Al₂O₃.

22. The acoustic resonator of claim 19 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.

23. The acoustic resonator of claim 19, wherein the recessed feature extends around a substantial portion of the perimeter of the passivation layer.