Surface acoustic wave device

Patent metadata

Field	Value
Publication number	US-9368712-B2
Application number	US-201213674114-A
Country	US
Kind code	B2
Filing date	Nov 12, 2012
Priority date	May 19, 2010
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

A surface acoustic wave device includes a piezoelectric substrate including a groove located in a surface thereof, an IDT electrode, and a dielectric film. The IDT electrode includes a first electrode layer located in the groove and a second electrode layer located outside the groove. The dielectric film is arranged on the piezoelectric substrate so as to cover the IDT electrode. The second electrode layer is tapered toward a side opposite to the piezoelectric substrate.

First claim

What is claimed is:

1. A surface acoustic wave device comprising:
a piezoelectric substrate including a groove located in a surface thereof;
an IDT electrode including a first electrode layer located in the groove and a second electrode layer located outside the groove; and
a dielectric film arranged on the piezoelectric substrate so as to cover the IDT electrode; wherein
the second electrode layer is tapered toward a side opposite to the piezoelectric substrate, and
a cross-sectional shape of the second electrode layer is trapezoidal, and a ratio T/R of a length T of an upper base to a length R of a lower base in a cross section of the second electrode layer is within a range of about 0.86 to about 0.98.

2. The surface acoustic wave device according to claim 1 , wherein the first electrode layer is tapered toward the piezoelectric substrate side.

3. The surface acoustic wave device according to claim 1 , wherein a ratio HT/R of a height HT to the length R of the lower base in the cross section of the second electrode layer is within a range of about 0.1 to about 0.25.

4. The surface acoustic wave device according to claim 2 , wherein a ratio HT/R of a height HT to the length R of the lower base in the cross section of the second electrode layer is within a range of about 0.1 to about 0.25.

5. The surface acoustic wave device according to claim 1 , wherein the dielectric film is made of silicon oxide or silicon nitride.

Assignees

• Murata Manufacturing Co

Inventors

• Kimura Tetsuya
• Ida Yasuyuki
• Saji Mari

Classifications

• H01L41/107 Primary

  Electricity · mapped topic

• H03H9/14541 Primary

  Multilayer finger or busbar electrode · CPC title

• H10N30/40 Primary

  with electrical input and electrical output, e.g. functioning as transformers · CPC title