Sezawa surface acoustic wave device using a piezoelectric layer over a nitride layer on a substrate

• US 4,571,519 A
• Filed: 11/30/1984
• Issued: 02/18/1986
• Est. Priority Date: 11/30/1983
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kawabata, Akira, Ieki, Hideharu, Fujishima, Satoru, Takeda, Fumio, Shiosaki, Tadashi
• Primary Examiner(s): Budd, Mark O.
• Application Number:
  US06/676,584
• Time in Patent Office: 445 Days
• Field of Search: 310/313 R, 310/313 A, 310/313 B, 310/313 C, 310/313 D, 333/150-155, 333/193-196
• US Class Current: 310/313.00A
• CPC Class Codes: H03H 9/02574 of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate

Abstract

A surface acoustic wave device comprising a surface acoustic wave substrate member composed by forming an aluminum nitride film and a thin zinc oxide film successively on a glass substrate. The thickness h₁ of the aluminum nitride film and the thickness h₂ of the zinc oxide film are set within ranges of 0.1≦h₁ /λ≦10 and 0.05≦h₂ /λ≦0.3 (where λ is representative of wavelength of Sezawa wave) respectively, thereby to utilize Sezawa wave or a similar mode wave transmitted on the surface acoustic wave substrate member in multi-layer structure.

Claims

1. A surface acoustic wave device comprising a surface acoustic wave substrate member composed by forming a nitride film and a piezoelectric thin film successively on a dielectric substrate, with thickness h₁ of said nitride film and thickness h₂ of said piezoelectric thin film being set within ranges of 0.1≦

h₁ /λ

≦

10 and 0.05≦

h₂ /λ

≦

0.3 respectively, thereby to utilize Sezawa wave or a similar mode wave transmitted on said surface acoustic wave substrate member in multi-layer structure,

wherein λ

is representative of wavelength of said Sezawa wave.

2. A surface acoustic wave device in accordance with claim 1, wherein said value h₁ /λ

is set within the range of 0.1≦

h₁ /λ

≦

1.0.

3. A surface acoustic wave device in accordance with claim 1, wherein said nitride film is formed by a thin film of aluminum nitride (AlN).

4. A surface acoustic wave device in accordance with claim 1, wherein said piezoelectric thin film is formed by a thin film of zinc oxide (ZnO).

5. A surface acoustic wave device in accordance with claim 1, wherein said dielectric substrate is formed by a glass substrate.