Elastic wave device, communication device, and piezoelectric substrate
To improve frequency characteristics of an elastic wave device. The elastic wave device includes a piezoelectric body having a first surface and an electrode including an IDT electrode on the first surface. The piezoelectric body has a first end surface connected to the first surface, the first end surface being an end surface positioned on a first side in a first direction that is orthogonal to an extending direction of any of electrode fingers. A first angle formed by an extended line of the first surface and a tangential line at any point on the first end surface is less than 90°.
1 . An elastic wave device comprising:
a piezoelectric substrate having a piezoelectric body having an upper surface and a first end surface connected to an upper surface, and
an electrode comprising an IDT electrode comprising a plurality of electrode fingers arrayed on the upper surface,
wherein the first end surface is positioned outside of the IDT electrode, as viewed in a plan view, in a first direction, the first direction is orthogonal to an extending direction of any of the plurality of electrode fingers, as viewed in the plan view,
a first angle formed by an extended line of the upper surface in the first direction and a tangential line at any point on the first end surface is 70° or greater and less than 90° on a cross-section obtained by cutting the piezoelectric body parallel to the first direction and perpendicular to the upper surface, and
the IDT electrode is not enclosed by the first end surface together with any other end surfaces of the piezoelectric body, as viewed in a plan view.
2 . The elastic wave device according to claim 1 , wherein the first angle is 80° or greater and less than 90°.
3 . The elastic wave device according to claim 1 , wherein the first angle is 88° or greater and less than 90°.
4 . The elastic wave device according to claim 1 , wherein
the piezoelectric substrate has a groove portion and the first end surface is a portion of the groove portion.
5 . The elastic wave device according to claim 1 , wherein,
the piezoelectric substrate has a support substrate and the support substrate is positioned on the piezoelectric body.
6 . The elastic wave device according to claim 5 , wherein
the support substrate has a first layer and a second layer positioned under the first layer.
7 . The elastic wave device according to claim 6 , wherein
a thickness of the second layer is greater than a thickness of the first layer.
8 . The elastic wave device according to claim 6 , wherein
the first layer has a second end surface positioned outside of the IDT electrode in the first direction.
9 . The elastic wave device according to claim 8 , wherein
the first end surface and the second end surface are continuous.
10 . The elastic wave device according to claim 8 comprising:
a groove portion of the piezoelectric substrate
the first end surface and the second end surface are portions of the groove portion.
11 . The elastic wave device according to claim 1 wherein
when an average value of intervals of the plurality of electrode fingers in the first direction is set to p, a height of the first end surface is 0.5 p or higher and 2.0 p or less.
12 . The elastic wave device according to claim 1 wherein
the electrode comprises an end-portion electrode closest to the first end surface, and
when an average value of intervals of the plurality of electrode fingers in the first direction is set to p, a shortest distance between the end-portion electrode and the first end surface is 5 p or shorter.
13 . The elastic wave device according to claim 12 , wherein
the shortest distance is 1 p or shorter.
14 . The elastic wave device according to claim 12 , wherein
the shortest distance is 0.1 p or shorter.
15 . The elastic wave device according to claim 1 , wherein
a grating reflector is not located between the IDT electrode and the first end surface in the first direction.
16 . An elastic wave device comprising:
a piezoelectric substrate having a piezoelectric body having an upper surface and a first end surface connected to the upper surface; and
an electrode comprising an IDT electrode comprising a plurality of electrode fingers arrayed on the upper surface,
wherein the first end surface is positioned outside of the IDT electrode, as viewed in a plan view, in a first direction the first direction is orthogonal to an extending direction of any of the plurality of electrode fingers, as viewed in the plan view,
a first angle formed by an extended line of the upper surface in the first direction and a tangential line at any point on the first end surface is less than 90° on a cross-section obtained by cutting the piezoelectric body parallel to the first direction and perpendicular to the upper surface,
when an average value of intervals of the plurality of electrode fingers in the first direction is set to p, a height of the first end surface is 0.5 p or higher and 2.0 p or less, and
the IDT electrode is not enclosed by the first end surface together with any other end surfaces of the piezoelectric body, as viewed in a plan view.
17 . An elastic wave device comprising:
a piezoelectric body having a piezoelectric body having an upper surface and a first end surface connected to the upper surface; and
an electrode comprising an IDT electrode comprising a plurality of electrode fingers arrayed on the upper surface,
wherein the first end surface is positioned outside of the IDT electrode, as viewed in a plan view, in a first direction the first direction is orthogonal to an extending direction of any of the plurality of electrode fingers, as viewed in the plan view,
a first angle formed by an extended line of the upper surface in the first direction and a tangential line at any point on the first end surface is less than 90° on a cross-section obtained by cutting the piezoelectric body parallel to the first direction and perpendicular to the upper surface,
wherein the electrode comprises an end-portion electrode closest to the first end surface,
when an average value of intervals of the plurality of electrode fingers in the first direction is set to p, a shortest distance between the end-portion electrode and the first end surface is 5 p or shorter, and
the IDT electrode is not enclosed by the first end surface together with any other end surfaces of the piezoelectric body, as viewed in a plan view.
18 . The elastic wave device according to claim 17 , wherein the shortest distance is 1 p or shorter.
19 . The elastic wave device according to claim 17 , wherein the shortest distance is 0.1 p or shorter.
20 . An elastic device comprising
a piezoelectric substrate having a piezoelectric body having an upper surface and a first end surface connected to an the upper surface, and
an electrode comprising an IDT electrode comprising a plurality of electrode fingers arrayed on the upper surface,
wherein the first end surface is positioned outside of the IDT electrode, as viewed in a plan view, in the first direction, the first direction is orthogonal to an extending direction of any of the plurality of electrode fingers, as viewed in a plan view,
a first angle formed by an extended line of the upper surface in the first direction and a tangential line at any point on the first end surface is 70° or greater and less than 90° on a cross-section obtained by cutting the piezoelectric body parallel to the first direction and perpendicular to the upper surface, and
wherein a grating reflector is not located between the IDT electrode and the first end surface in the first direction.
21 . The elastic wave device according to claim 20 , wherein the first angle is 80° or greater and less than 90°.
22 . The elastic wave device according to claim 20 , wherein the first angle is 88° or greater and less than 90°.
23 . The elastic wave device according to claim 20 , wherein the piezoelectric substrate has a groove portion and the first end surface is a portion of the groove portion.
24 . The elastic wave device according to claim 20 , wherein the piezoelectric substrate has a support substrate and the support substrate is positioned on the piezoelectric body.
25 . The elastic wave device according to claim 24 , wherein the support substrate has a first layer and a second layer positioned under the first layer.
26 . The elastic wave device according to claim 25 , wherein a thickness of the second layer is greater than a thickness of the first layer.
27 . The elastic wave device according to claim 25 , wherein the first layer has a second end surface positioned outside of the IDT electrode in the first direction.
28 . The elastic wave device according to claim 27 , wherein the first end surface and the second end surface are continuous.
29 . The elastic wave device according to claim 27 , comprising a groove portion of the piezoelectric substrate, and
wherein the first end surface and the second end surface are portion of the groove portion.