Surface acoustic wave device and method for producing the same

• US 5,329,208 A
• Filed: 06/05/1992
• Issued: 07/12/1994
• Est. Priority Date: 06/05/1991
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Nakahata, Hideaki, Hachigo, Akihiro, Imai, Takahiro, Fujimori, Naoji
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US07/894,598
• Time in Patent Office: 767 Days
• Field of Search: 310/313 A, 310/313 R
• US Class Current: 310/313.00R
• CPC Class Codes: H03H 9/02582 of diamond substrates
• CPC Class Codes: H03H 9/02622 of the surface, including back surface
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A surface acoustic wave device having a diamond layer, a piezoelectric layer and a comb-like electrode, in which the piezoelectric layer and the comb-like electrode are formed on a surface of the diamond layer, which surface has been contacted to a substrate used in the formation of the diamond layer by a vapor phase growth method, which device has high stability and can be produced economically.

Claims

1. A surface acoustic wave device comprising a diamond layer, a piezoelectric layer and a comb-like electrode, wherein said piezoelectric layer and said comb-like electrode are formed on a surface of said diamond layer, said surface having been in contact with a substrate used in the formation of said diamond layer by a vapor phase growth method, resulting in said surface having a surface roughness of 0.1 μ

m or less.

2. The surface acoustic wave device according to claim 1, wherein said diamond layer has a thickness of at least 5 μ

m.

3. The surface acoustic wave device according to claim 1, wherein said diamond layer has a resistivity of at least 10⁶ Ω

.cm.

4. The surface acoustic wave device according to claim 1, wherein said piezoelectric layer is made of at least one material selected from ZnO, AlN, PZT, PLZT, SiO₂, LiTaO₃ and LiNbO₃.

5. The surface acoustic wave device according to claim 1, wherein said piezoelectric layer has a resistivity of at least 10⁴ Ω

.cm.

6. A surface acoustic wave device comprising:

a diamond layer having an exterior surface that has been etched from an adjoining substrate so as to have a surface roughness of 0.1 μ

m or less;

a piezoelectric layer on the exterior surface of said diamond layer; and

a comb-like electrode on the exterior surface of said diamond layer.