Composite substrates for acoustic wave elements, and acoustic wave elements

Patent metadata

Field	Value
Publication number	US-9438201-B2
Application number	US-201514835938-A
Country	US
Kind code	B2
Filing date	Aug 26, 2015
Priority date	Mar 21, 2013
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

A composite substrate for an acoustic wave element includes a support substrate 1 and a propagation substrate 3 for propagating an acoustic wave. The propagation substrate is bonded to the support substrate 1 and composed of a piezoelectric single crystal. The propagation substrate 3 includes a surface lattice distortion layer 11 in which crystal lattices of the piezoelectric single crystal are distorted.

First claim

The invention claimed is:

1. A composite substrate for an acoustic wave element: said acoustic wave element comprising a support substrate and a propagation substrate for propagating an acoustic wave, said propagation substrate being bonded to said support substrate and comprising a piezoelectric single crystal;
wherein said propagation substrate comprises a bonding face to be bonded to said support substrate and a surface on the opposite side of said bonding face;
wherein said propagation substrate comprises a surface lattice distortion layer on the side of said surface on the opposite side of said bonding face and in which crystal lattices of said piezoelectric single crystal are distorted; and
wherein said surface lattice distortion layer has a thickness of 15 nm or smaller.

2. The composite substrate of claim 1 , wherein said thickness of said surface lattice distortion layer is 3 nm or smaller.

3. The composite substrate of claim 1 , wherein said surface lattice distortion layer comprises a plurality of layers observed by a transmittance type electron microscope.

4. The composite substrate of claim 1 , wherein said acoustic wave comprises a surface acoustic wave, a Lamb wave-type acoustic wave or a bulk acoustic wave.

5. The composite substrate of claim 4 , wherein said acoustic wave element comprises a surface acoustic wave filter or a resonator.

6. The composite substrate of claim 1 , wherein said support substrate and said propagation substrate are bonded to each other directly or through an adhesive layer.

7. The composite substrate of claim 6 , wherein said adhesive layer comprises an organic adhesive layer having a thickness of 0.1 to 1.0 μm.

8. The composite substrate of claim 1 , wherein said piezoelectric single crystal is selected from the group consisting of single crystals of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate solid solution.

9. The composite substrate of claim 1 , wherein said support substrate comprises a material selected from the group consisting of silicon, sapphire, aluminum nitride sintered body, alumina, silicon carbide sintered body, silicon nitride sintered body, borosilicate glass and quartz glass.

10. The composite substrate of claim 1 , wherein said propagation substrate has a thickness of 0.1 to 40 μm.

11. The composite substrate of claim 1 , wherein said acoustic wave element comprises an electrode pattern provided on said propagation substrate.

12. The composite substrate of claim 11 , wherein said acoustic wave element comprises a surface acoustic wave filter or a resonator.

Assignees

• Ngk Insulators Ltd

Inventors

• Hori Yuji
• Tai Tomoyoshi

Classifications

• H03H9/02834 Primary

  of temperature influence (cut angles H03H9/02543) · CPC title

• H03H9/02574

  of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate · CPC title

• H03H9/02102 Primary

  of temperature influence (cutting angles H03H9/02015) · CPC title

• H03H9/02228

  Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer · CPC title

• H03H9/25

  Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)} · CPC title