Acoustic wave device including electrode films with different surface angles and widths
AssigneeMurata Manufacturing Co., Ltd.
InventorMinefumi Ouchi
Life of this patent
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Abstract
An acoustic wave device includes a piezoelectric layer including first and second main surfaces and made of lithium niobate or lithium tantalate, and an interdigital transducer electrode on the first main surface and including multiple electrode fingers. d/p is about 0.5 or less where d is a thickness of the piezoelectric layer, and p is a distance between centers of adjacent electrode fingers. The electrode fingers include first and second electrode films, which include first and second surfaces and a side surface. Θ1≠Θ2 is satisfied and W1>W2 is satisfied, where Θ1 and Θ2 are angles between the side surfaces and the first surfaces of the first and second electrode films, and W1 and W2 are widths of the first and second electrode films.
Claims14
A filter device comprising:
- a plurality of acoustic wave resonators;
- wherein
- the plurality of acoustic wave resonators include all acoustic wave resonators included in the filter device;
- each of the plurality of acoustic wave resonators is an acoustic wave device including:
- a piezoelectric layer including a first main surface and a second main surface facing away from each other and made of lithium niobate or lithium tantalate;
- and
- an interdigital transducer electrode on the first main surface of the piezoelectric layer and including a plurality of electrode fingers;
- in each of the acoustic wave devices of the plurality of acoustic wave resonators:
- d/p is about 0.5 or less, where d is a thickness of the piezoelectric layer, and p is a distance between centers of adjacent electrode fingers of the plurality of electrode fingers;
- the plurality of electrode fingers include a first electrode film and a second electrode film on the first electrode film;
- the first electrode film and the second electrode film each include a first surface and a second surface facing away from each other in a thickness direction and a side surface connected to the first surface and the second surface;
- Θ1+Θ2 is satisfied and W1>W2 is satisfied, where Θ1 is an angle between the side surface and the first surface of the first electrode film, Θ2 is an angle between the side surface and the first surface of the second electrode film, W1 is a width of the first electrode film, and W2 is a width of the second electrode film;
- and
- a ratio W1/W2 between the width W1 of the first electrode film and the width W2 of the second electrode film differs between at least two of the plurality of acoustic wave resonators.
A filter device comprising:
- a plurality of acoustic wave resonators;
- wherein
- the plurality of acoustic wave resonators include all acoustic wave resonators included in the filter device;
- each of the plurality of acoustic wave resonators is an acoustic wave device including:
- a piezoelectric layer including a first main surface and a second main surface facing away from each other and made of lithium niobate or lithium tantalate;
- and
- an interdigital transducer electrode on the first main surface of the piezoelectric layer and including a plurality of electrode fingers;
- and
- in each of the acoustic wave devices of the plurality of acoustic wave resonators:
- d/p is about 0.5 or less, where d is a thickness of the piezoelectric layer, and p is a distance between centers of adjacent electrode fingers of the plurality of electrode fingers;
- the plurality of electrode fingers include a first electrode film and a second electrode film on the first electrode film;
- the first electrode film and the second electrode film each include a first surface and a second surface facing away from each other in a thickness direction and a side surface connected to the first surface and the second surface;
- Θ1≠Θ2 is satisfied and W1>W2 is satisfied, where Θ1 is an angle between the side surface and the first surface of the first electrode film, Θ2 is an angle between the side surface and the first surface of the second electrode film, W1 is a width of the first electrode film, and W2 is a width of the second electrode film;
- and
- the angle Θ2 differs between at least two of the plurality of acoustic wave resonators.
Dependencies are inferred from the claim text.