Film bulk acoustic resonator with improved lateral mode suppression

• US 6,693,500 B2
• Filed: 04/16/2002
• Issued: 02/17/2004
• Est. Priority Date: 06/25/2001
• Status: Expired due to Term

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kim, Hong Wook, Yang, Doo Yeoul
• Primary Examiner(s): Cunningham, Terry D.
• Assistant Examiner(s): TRA, ANH QUAN
• Application Number:
  US10/122,241
• Publication Number:
  US 20020196103A1
• Time in Patent Office: 672 Days
• Field of Search: 333/186-192, 310/320-324, 310/349, 310/351, 310/353, 310/365, 310/366, 310/334, 310/335, 310/311
• US Class Current: 333/189
• CPC Class Codes: H03H 9/173 Air-gaps

Abstract

A film bulk acoustic resonator includes a substrate, a membrane, a piezoelectric layer and a pair of electrodes. The membrane is formed on the substrate to form an air gap. The piezoelectric layer is formed on the membrane. The electrodes are formed on both surfaces of the piezoelectric layer to partially overlap each other. All the sides of the piezoelectric layer and the electrodes are curved.

Claims

1. A film bulk acoustic resonator (FBAR), comprising:

a piezoelectric layer;

a pair of electrodes being formed on opposite surfaces of the piezoelectric layer and partially overlapping each other;

a substrate; and

a supporting layer formed on the substrate and provided with a certain internal space;

wherein

the piezoelectric layer is formed on the supporting layer; and

all sides of at least one of the electrodes and the piezoelectric layer are curved.

2. The FBAR according to claim 1, wherein

the supporting layer comprises a membrane supporting layer formed on the substrate and provided with a certain cavity region and a membrane layer formed on the membrane supporting layer, and

the piezoelectric layer is formed on the membrane layer to include a region corresponding to the cavity region.

3. A film bulk acoustic resonator, comprising:

a substrate;

a supporting layer formed on the substrate to form an air gap;

at least two piezoelectric layers formed on the supporting layer; and

a pair of electrodes formed on both surfaces of the piezoelectric layer to be partially opposite and overlapped;

wherein all sides of at least one of the electrodes and/or all sides of at least one of the piezoelectric layers are curved.

4. A filter, comprising:

a plurality of FBARs, the FBARs being set force in claim 3 and connected in parallel or series with one another.