Electronic device on substrate with cavity and mitigated parasitic leakage path

• US 7,479,685 B2
• Filed: 03/10/2006
• Issued: 01/20/2009
• Est. Priority Date: 03/10/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Wade, Christopher P., Ruby, Richard C., Feld, David A., Frank, Michael Louis, Fazzio, R. Shane
• Primary Examiner(s): Pert; Evan
• Assistant Examiner(s): Tran; Tan N
• Application Number:
  US11/373,434
• Publication Number:
  US 20070236310A1
• Time in Patent Office: 1,047 Days
• Field of Search: 257/416, 257/245, 333/187, 310/311, 310/324, 310/348
• US Class Current: 257/416
• CPC Class Codes: H03H 3/02 for the manufacture of piezoelectric or electrostrictive resonators or networks H03H3/08 takes precedence
• CPC Class Codes: H03H 9/02118 of lateral leakage between adjacent resonators
• CPC Class Codes: H03H 9/02125 of parasitic elements
• CPC Class Codes: H03H 9/172 Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume

Abstract

An electronic device. The electronic device includes a first electrode and a coating layer. The electronic device is fabricated on a substrate; the substrate has a cavity created in a top surface of the substrate; and the first electrode is electrically coupled to the substrate. The coating layer coats at least part of a substrate surface in the cavity, and the presence of the coating layer results in a mitigation of at least one parasitic leakage path between the first electrode and an additional electrode fabricated on the substrate.

Claims

1. A thin film bulk acoustic resonator, comprising:

a first electrode, wherein the thin film bulk acoustic resonator is fabricated on a substrate and wherein the substrate has a cavity created in a top surface of the substrate;

a piezoelectric layer overlying at least part of the first electrode;

a second electrode overlying at least part of the piezoelectric layer;

a coating layer comprising multiple layers, comprising;

a first layer comprising silicon dioxide that overlays at least a part of the substrate surface in the cavity and a second layer comprising aluminum nitride that overlays at least part of the first layer, wherein the coating layer coats at least part of a substrate surface in the cavity.

2. The thin film bulk acoustic resonator as recited in claim 1, wherein the presence of the coating layer results in a mitigation of at least one parasitic leakage path between the first electrode and an additional electrode fabricated on the substrate.

3. The thin film bulk acoustic resonator as recited in claim 1, wherein the cavity is connected by at least one channel to at least one release opening wherein the at least one release opening enables removal of a sacrificial material, and wherein the coating layer covers at least part of the walls of the at least one channel.

4. The thin film bulk acoustic resonator as recited in claim 1, wherein the coating layer material is selected from the group of materials consisting of a dielectric material, a semiconductor material, a conductive material, a metal, a ceramic, an implanted material, silicon dioxide, silicon nitride, aluminum nitride, molybdenum, and gold.

5. The thin film bulk acoustic resonator as recited in claim 1, wherein the coating layer is attachable to a fixed electrical potential.

6. The thin film bulk acoustic resonator as recited in claim 1, wherein the substrate is selected from the group consisting of a semiconductor, a semiconductor wafer, silicon, a silicon wafer, and a ceramic substrate.

7. The thin film bulk acoustic resonator as recited in claim 1, wherein the coating layer further overlies at least a part of the top surface of the substrate.