Elastic wave device and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9831848-B2
Application number	US-201615212489-A
Country	US
Kind code	B2
Filing date	Jul 18, 2016
Priority date	Dec 24, 2010
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.

First claim

What is claimed is:

1. An elastic wave device including a piezoelectric film, the elastic wave device comprising:
a high-acoustic-velocity supporting substrate in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in the piezoelectric film;
a low-acoustic-velocity film stacked on the high-acoustic-velocity supporting substrate;
the piezoelectric film stacked on the low-acoustic-velocity film; and
an IDT electrode disposed on a surface of the piezoelectric film; wherein
a thickness of the low-acoustic-velocity film stacked on the high-acoustic-velocity supporting substrate and disposed under the piezoelectric film is in a range of about 0.1λ to about 0.5λ, where λ is a wavelength of an elastic wave determined by an electrode period of the IDT electrode;
the piezoelectric film includes at least one of LiTaO 3 , LiNbO 3 , ZnO, AlN, and PZT; and
the low-acoustic-velocity film includes at least one of silicon oxide, glass, silicon oxynitride, tantalum oxide, and any material obtained by adding fluorine, carbon, or boron to silicon oxide.

2. The elastic wave device according to claim 1 , wherein a thickness of the piezoelectric film is about 1.5λ or less.

3. The elastic wave device according to claim 1 , wherein the elastic wave device further includes at least one of an adhesion layer, an underlying film, and a medium layer.

4. The elastic wave device according to claim 3 , wherein the medium layer is composed of a metal.

5. The elastic wave device according to claim 1 , wherein the thickness of the low-acoustic-velocity film stacked on the high-acoustic-velocity supporting substrate and disposed under the piezoelectric film is in a range of about 0.2λ to about 0.5λ.

6. An elastic wave device including a piezoelectric film, the elastic wave device comprising:
a supporting substrate;
a high-acoustic-velocity film disposed on the supporting substrate, in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in the piezoelectric film;
a low-acoustic-velocity film stacked on the high-acoustic-velocity film;
the piezoelectric film stacked on the low-acoustic-velocity film; and
an IDT electrode disposed on a surface of the piezoelectric film; wherein
a thickness of the low-acoustic-velocity film stacked on the high-acoustic-velocity film and disposed under the piezoelectric film is in a range of about 0.1λ to about 0.5λ, where λ is a wavelength of an elastic wave determined by an electrode period of the IDT electrode;
the piezoelectric film includes at least one of LiTaO 3 , LiNbO 3 , ZnO, AlN, and PZT; and
the low-acoustic-velocity film includes at least one of silicon oxide, glass, silicon oxynitride, tantalum oxide, and any material obtained by adding fluorine, carbon, or boron to silicon oxide.

7. The elastic wave device according to claim 6 , wherein a thickness of the piezoelectric film is about 1.5λ or less.

8. The elastic wave device according to claim 6 , wherein the elastic wave device further includes at least one of an adhesion layer, an underlying film, and a medium layer.

9. The elastic wave device according to claim 8 , wherein the medium layer is composed of a metal.

10. The elastic wave device according to claim 6 , wherein the thickness of the low-acoustic-velocity film stacked on the high-acoustic-velocity film and disposed under the piezoelectric film is in a range of about 0.2λ to about 0.5λ.

11. The elastic wave device according to claim 1 , wherein a material of the high-acoustic-velocity supporting substrate includes at least one of silicon, sapphire, alumina, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mullite, steatite, forsterite, dielectrics, and gallium nitride.

12. An elastic wave device comprising:
a high-acoustic-velocity supporting substrate;
a piezoelectric film indirectly stacked on the high-acoustic-velocity supporting substrate;
an IDT electrode disposed on the piezoelectric film; and
a low-acoustic-velocity film stacked between the piezoelectric film and the high-acoustic-velocity supporting substrate; wherein
a material of the piezoelectric film includes at least one of LiTaO 3 , LiNbO 3 , ZnO, AlN, and PZT;
a material of the low-acoustic-velocity film includes at least one of silicon oxide, glass, silicon oxynitride, and tantalum oxide;
a material of the high-acoustic-velocity supporting substrate includes at least one of silicon, sapphire, alumina, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mullite, steatite, forsterite, dielectrics, and gallium nitride; and
a thickness of the low-acoustic-velocity film is in a range of about 0.1λ to about 0.5λ, where λ is a wavelength of an elastic wave determined by an electrode period of the IDT electrode.

13. The elastic wave device according to claim 12 , wherein the low-acoustic-velocity film is stacked on the high-acoustic-velocity supporting substrate.

14. The elastic wave device according to claim 12 , wherein a thickness of the piezoelectric film is about 1.5λ or less.

15. The elastic wave device according to claim 12 , wherein the elastic wave device further includes at least one of an adhesion layer, an underlying film, and a medium layer.

16. The elastic wave device according to claim 15 , wherein the medium layer is composed of a metal.

17. The elastic wave device according to claim 12 , wherein the thickness of the low-acoustic-velocity film is in a range of about 0.2λ to about 0.5λ.

18. An elastic wave device comprising:
a supporting substrate;
a high-acoustic-velocity film directly or indirectly stacked on the supporting substrate;
a piezoelectric film indirectly stacked on the high-acoustic-velocity film;
an IDT electrode disposed on the piezoelectric film; and
a low-acoustic-velocity film stacked between the piezoelectric film and the high-acoustic-velocity film; wherein
a material of the piezoelectric film includes at least one of LiTaO 3 , LiNbO 3 , ZnO, AlN, and PZT;
a material of the low-acoustic-velocity film includes at least one of silicon oxide, glass, silicon oxynitride, and tantalum oxide;
a material of the high-acoustic-velocity film includes at least one of silicon, sapphire, or alumina, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mullite, steatite, forsterite, dielectrics, and gallium nitride; and
a thickness of the low-acoustic-velocity film is in a range of about 0.1λ to about 0.5λ, where λ is a wavelength of an elastic wave determined by an electrode period of the IDT electrode.

19. The elastic wave device according to claim 18 , wherein the low-acoustic-velocity film is stacked on the high-acoustic-velocity film.

20. The elastic wave device according to claim 18 , wherein a thickness of the piezoelectric film is about 1.5λ or less.

21. The elastic wave device according to claim 18 , wherein the elastic wave device further includes at least one of an adhesion layer, an underlying film, and a medium layer.

22. The elastic wave device according to claim 21 , wherein the medium layer is composed of a metal.

23. The elastic wave device according to claim 18 , wherein the thickness of the low-acoustic-velocity film is in a range of about 0.2λ to about 0.5λ.

Assignees

• Murata Manufacturing Co

Inventors

• Watanabe Munehisa
• Iwamoto Hideki
• Kando Hajime
• Kido Syunsuke

Classifications

• H03H3/10 Primary

  for obtaining desired frequency or temperature coefficient · CPC title

• H03H2003/023

  the resonators or networks being of the membrane type · CPC title

• Y10T29/49155

  Manufacturing circuit on or in base · CPC title

• H03H9/0222 Primary

  of interface-acoustic, boundary, pseudo-acoustic or Stonely wave devices · CPC title

• H03H3/08

  for the manufacture of resonators or networks using surface acoustic waves · CPC title