Elastic wave device
An elastic wave device includes an IDT electrode provided on a main surface of a LiTaO 3 substrate, and uses plate waves in an SH0 mode, which is a basic mode of SH waves. A wavelength-normalized thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode, and an Al equivalent wavelength-normalized thickness of the IDT electrode satisfy any one of combinations listed in the following table: (a) The wavelength-normalized thickness is about 0.01 or more and about 0.30 or less, and the wavelength- normalized thickness of Al is about 0.04 or more and about 0.1 or less. (b) The wavelength-normalized thickness is about 0.01 or more and about 0.70 or less, and the wavelength- normalized thickness of Al is about 0.04 or more and about 0.08 or less.
1. An elastic wave device comprising: a LiTaO 3 substrate; and an IDT electrode provided on a main surface of the LiTaO 3 substrate and made of Al or predominantly made of Al; and a conductive film provided on a second main surface of the LiTaO 3 substrate so as to be opposed to the IDT electrode across the LiTaO 3 substrate; wherein the elastic wave device uses a plate wave in an SHO mode that is a basic mode of SH waves; and a wavelength-normalized thickness of the LiTaO 3 substrate that is a thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode and an Al equivalent wavelength-normalized thickness of the IDT electrode satisfy any one of combinations listed in Table 1:
TABLE 1
(a)
The wavelength-normalized thickness is about 0.01 or
more and about 0.30 or less, and the wavelength-
normalized thickness of Al is about 0.04 or more and
about 0.1 or less
(b)
The wavelength-normalized thickness is about 0.01 or
more and about 0.70 or less, and the wavelength-
normalized thickness of Al is about 0.04 or more and
about 0.08 or less.
2. The elastic wave device according to claim 1 , wherein Euler angles of the LiTaO 3 substrate are within the ranges of (0°±5°, 120°±10°, 0°±5°).
3. The elastic wave device according to claim 1 , wherein the conductive film is another IDT electrode.
4. The elastic wave device according to claim 1 , wherein a duty of the IDT electrode is about 0.5.
5. An elastic wave device comprising: a LiTaO 3 substrate; and an IDT electrode provided on a main surface of the LiTaO 3 substrate and made of Al or predominantly made of Al; and a conductive film provided on a second main surface of the LiTaO 3 substrate so as to be opposed to the IDT electrode across the LiTaO 3 substrate; wherein the elastic wave device uses a plate wave in an SHO mode that is a basic mode of SH waves; and a wavelength-normalized thickness of the LiTaO 3 substrate that is a thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode and a duty of the IDT electrode satisfy any one of combinations listed in Table 2:
TABLE 2
(a)
The wavelength-normalized thickness is about 0.07 or
more and about 0.21 or less, and the duty is about 0.3
or more and about 0.7 or less
(b)
The wavelength-normalized thickness is about 0.03 or
more and about 0.27 or less, and the duty is about 0.3
or more and about 0.6 or less
(c)
The wavelength-normalized thickness is about 0.01 or
more and about 0.30 or less, and the duty is about 0.3
or more and about 0.5 or less
(d)
The wavelength-normalized thickness is about 0.01 or
more and about 0.32 or less, and the duty is about 0.3
or more and about 0.4 or less.
6. The elastic wave device according to claim 5 , wherein Euler angles of the LiTaO 3 substrate are within the ranges of (0°±5°, 120°±10°, 0°±5°).
7. The elastic wave device according to claim 5 , wherein the conductive film is another IDT electrode.
8. An elastic wave device comprising: a LiTaO 3 substrate including a first main surface and a second main surface on an opposite side of the first main surface; an IDT electrode provided on the first main surface of the LiTaO 3 substrate and made of Al or predominantly made of Al; and a conductive film provided on the second main surface of the LiTaO 3 substrate so as to be opposed to the IDT electrode across the LiTaO 3 substrate; wherein the elastic wave device uses a plate wave in an SHO mode that is a basic mode of SH waves; the conductive film is not short-circuited; and a wavelength-normalized thickness of the LiTaO 3 substrate that is a thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode and an Al equivalent wavelength-normalized thickness of the IDT electrode satisfy any one of combinations listed in Table 3:
TABLE 3
(a)
The wavelength-normalized thickness is about 0.01 or
more and about 0.59 or less, and the wavelength-
normalized thickness of Al is about 0.04 or more and
about 0.1 or less
(b)
The wavelength-normalized thickness is about 0.01 or
more and about 0.70 or less, and the wavelength-
normalized thickness of Al is about 0.04 or more and
about 0.08 or less.
9. The elastic wave device according to claim 8 , wherein Euler angles of the LiTaO 3 substrate are within the ranges of (0°±5°, 120°±10°, 0°±5°).
10. The elastic wave device according to claim 8 , wherein another IDT electrode is provided on another main surface of the LiTaO 3 substrate.
11. The elastic wave device according to claim 8 , wherein the conductive film is made of Al and has a thickness of about 50 nm.
12. An elastic wave device comprising: a LiTaO 3 substrate including a first main surface and a second main surface on an opposite side of the first main surface; an IDT electrode provided on the first main surface of the LiTaO 3 substrate and made of Al or predominantly made of Al; and a conductive film provided on the second main surface of the LiTaO 3 substrate so as to be opposed to the IDT electrode across the LiTaO 3 substrate; wherein the elastic wave device uses a plate wave in an SHO mode that is a basic mode of SH waves; the conductive film is not short-circuited; and a wavelength-normalized thickness of the LiTaO 3 substrate that is a thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode and a duty of the IDT electrode satisfy any one of combinations listed in Table 4:
TABLE 4
(a)
The wavelength-normalized thickness is about 0.05 or
more and about 0.45 or less, and the duty is about 0.3
or more and about 0.7 or less
(b)
The wavelength-normalized thickness is about 0.02 or
more and about 0.52 or less, and the duty is about 0.3
or more and about 0.6 or less
(c)
The wavelength-normalized thickness is about 0.01 or
more and about 0.58 or less, and the duty is about 0.3
or more and about 0.5 or less
(d)
The wavelength-normalized thickness is about 0.01 or
more and about 0.66 or less, and the duty is about 0.3
or more and about 0.4 or less.
13. The elastic wave device according to claim 12 , wherein Euler angles of the LiTaO 3 substrate are within the ranges of (0°±5°, 120°±10°, 0°±5°).
14. The elastic wave device according to claim 12 , wherein another IDT electrode is provided on another main surface of the LiTaO 3 substrate.
15. The elastic wave device according to claim 12 , wherein the conductive film is made of Al and has a thickness of about 50 nm.
16. An elastic wave device comprising: a LiTaO 3 substrate including a first main surface and a second main surface on an opposite side of the first main surface; an IDT electrode provided on the first main surface of the LiTaO 3 substrate and made of Al or predominantly made of Al; and a conductive film provided on the second main surface of the LiTaO 3 substrate so as to be opposed to the IDT electrode across the LiTaO 3 substrate; wherein the elastic wave device uses a plate wave in an SHO mode that is a basic mode of SH waves; the conductive film is short-circuited; and a wavelength-normalized thickness of the LiTaO 3 substrate that is a thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode and an Al equivalent wavelength-normalized thickness of the IDT electrode satisfy any one of combinations listed in Table 5:
TABLE 5
(a)
The wavelength-normalized thickness is about 0.01 or
more and about 0.7 or less, and the wavelength-
normalized thickness of Al is about 0.04 or more and
about 0.1 or less.
17. The elastic wave device according to claim 16 , wherein Euler angles of the LiTaO 3 substrate are within the ranges of (0°±5°, 120°±10°, 0°±5°).
18. The elastic wave device according to claim 16 , wherein another IDT electrode is provided on another main surface of the LiTaO 3 substrate.
19. The elastic wave device according to claim 16 , wherein the conductive film is made of Al and has a thickness of about 50 nm.
20. An elastic wave device comprising: a LiTaO 3 substrate including a first main surface and a second main surface on an opposite side of the first main surface; an IDT electrode provided on the first main surface of the LiTaO 3 substrate and made of Al or predominantly made of Al; and a conductive film provided on the second main surface of the LiTaO 3 substrate so as to be opposed to the IDT electrode across the LiTaO 3 substrate; wherein the elastic wave device uses a plate wave in an SHO mode that is a basic mode of SH waves; the conductive film is short-circuited; and a wavelength-normalized thickness of the LiTaO 3 substrate that is a thickness of the LiTaO 3 substrate normalized by a wavelength determined by a pitch of electrode fingers of the IDT electrode and a duty of the IDT electrode satisfy any one of combinations in Table 6:
TABLE 6
(a)
The wavelength-normalized thickness is about 0.05 or
more and about 0.60 or less, and the duty is about 0.3
or more and about 0.7 or less
(b)
The wavelength-normalized thickness is about 0.02 or
more and about 0.68 or less, and the duty is about 0.3
or more and about 0.6 or less
(c)
The wavelength-normalized thickness is about 0.01 or
more and about 0.70 or less, and the duty is about 0.3
or more and about 0.5 or less.