Elastic wave device and manufacturing method for same
AssigneeMurata Manufacturing Co., Ltd.
InventorsHajime Kando, Syunsuke Kido, Keiji Okada, Munehisa Watanabe
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Abstract
An elastic wave device includes a support layer with a through-hole or a recess opened at an upper surface thereof, a piezoelectric thin film arranged on the support layer to extend above the recess or the through-hole of the support layer, and an IDT electrode defined on at least one of upper and lower surfaces of the piezoelectric thin film in a region of the piezoelectric thin film, the region extending above the recess, or the through-hole. A secondary mode of a plate wave, which contains a U1 component as a main component, is utilized. The piezoelectric thin film is made of LiTaO3, and Euler angles (φ, θ, ψ) of the LiTaO3 fall within specific ranges.
Claims19
An elastic wave device comprising:
- a support layer including a through-hole or a recess opened at an upper surface thereof;
- a piezoelectric thin film arranged on the support layer to extend above the recess or the through-hole of the support layer;
- and
- an IDT electrode provided on at least one of upper and lower surfaces of the piezoelectric thin film in a region of the piezoelectric thin film that extends above the recess or the through-hole;
- wherein
- an elastic wave propagating in the piezoelectric thin film is a secondary mode of a plate wave that contains a U1 component as a main component of displacement;
- a propagation velocity of the secondary mode of the plate wave is about 7000 meters per second or more;
- the piezoelectric thin film is made of LiTaO3;
- and
- Euler angles (φ, θ, ψ) of the LiTaO3 fall within any of ranges represented by regions R1 to R7 surrounded by solid lines in FIGS. 4 to 10.
An elastic wave device comprising:
- a support layer including a through-hole or a recess opened at an upper surface thereof;
- a piezoelectric thin film arranged on the support layer to extend above the recess or the through-hole of the support layer;
- and
- an IDT electrode provided on at least one of upper and lower surfaces of the piezoelectric thin film in a region of the piezoelectric thin film that extends above the recess or the through-hole;
- wherein
- a secondary mode of a plate wave, which contains a U1 component as a main component of displacement, is utilized, the piezoelectric thin film is made of LiTaO3, and Euler angles (φ, θ, ψ) of the LiTaO3 fall within specific ranges, where φ is in a range of about 0° to about 30° and θ is in a range of about 0° to about 55° or a range of about 140° to about 180°;
- when θ is in a range of about 0° to about 55°, ψ is in a range of about 180° to about 110°, a range of about 100° to about 50°, or a range of about 40° to about 0°;
- when θ is in a range of about 140° to about 180°, ψ is in a range of about 180° to about 20° or a range of about 10° to about 0°;
- and
- a propagation velocity of the secondary mode of the plate wave is about 7000 meters per second or more.
Dependencies are inferred from the claim text.