Surface acoustic wave device
Aspects of this disclosure relate to a surface acoustic wave device. The surface acoustic wave device includes a piezoelectric layer and an interdigital transducer. The interdigital transducer electrode includes a pair of electrodes, each electrode having a bus bar and fingers extending from the bus bar. The interdigital transducer electrode has an interdigital region defined by a portion of the fingers of the electrodes that interdigitate with each other. A dielectric layer is disposed over the interdigital transducer electrode outside the interdigital region and configured to reduce a loss of the surface acoustic wave device.
1. A surface acoustic wave device comprising:
a piezoelectric layer;
an interdigital transducer electrode on the piezoelectric layer, the interdigital transducer electrode including a pair of electrodes, each electrode having a bus bar and fingers extending from the bus bar, the interdigital transducer electrode having an interdigital region defined by a portion of the fingers of the electrodes that interdigitate with each other;
a dielectric layer disposed over the interdigital transducer electrode outside the interdigital region and configured to reduce a loss of the surface acoustic wave device;
a functional layer below the piezoelectric layer and a support substrate layer below the functional layer.
2. The surface acoustic wave device of claim 1 wherein the dielectric layer is a tantalum pentoxide layer.
3. The surface acoustic wave device of claim 1 wherein the piezoelectric layer is one of a lithium tantalate layer and a lithium niobate layer.
4. The surface acoustic wave device of claim 1 wherein the functional layer is a silicon dioxide layer.
5. The surface acoustic wave device of claim 1 wherein the functional layer includes a first functional layer and a second functional layer, and the surface acoustic wave device further including a metal layer between the first functional layer and the second functional layer.
6. The surface acoustic wave device of claim 1 further including a silicon dioxide layer disposed over the interdigital transducer electrode, the dielectric layer disposed over the silicon dioxide layer.
7. The surface acoustic wave device of claim 1 wherein the dielectric layer is disposed over the bus bar of the interdigital transducer electrode.
8. The surface acoustic wave device of claim 7 wherein the dielectric layer is disposed at least over a dummy region of the interdigital transducer electrode, or a gap region of the interdigital transducer electrode.
9. The surface acoustic wave device of claim 1 wherein the dielectric layer is disposed over a gap region of the interdigital transducer electrode.
10. A surface acoustic wave device comprising:
a piezoelectric layer;
an interdigital transducer electrode on the piezoelectric layer, the interdigital transducer electrode including a pair of electrodes, each electrode having a bus bar and fingers extending from the bus bar, the interdigital transducer electrode having an interdigital region defined by a portion of the fingers of the electrodes that interdigitate with each other; and
a dielectric layer disposed over the interdigital transducer electrode outside the interdigital region and configured to reduce a loss of the surface acoustic wave device, the dielectric layer disposed over a dummy region of the interdigital transducer electrode.
11. The surface acoustic wave device of claim 10 wherein the dielectric layer is disposed over the dummy region and a gap region of the interdigital transducer electrode.
12. A surface acoustic wave device comprising:
a piezoelectric layer;
an interdigital transducer electrode on the piezoelectric layer, the interdigital transducer electrode including a pair of electrodes, each electrode having a bus bar and fingers extending from the bus bar, the interdigital transducer electrode having an interdigital region defined by a portion of the fingers of the electrodes that interdigitate with each other; and
a dielectric layer disposed over the interdigital transducer electrode outside the interdigital region and configured to reduce a loss of the surface acoustic wave device, the dielectric layer having a thickness of between 0.01L and 0.04L, L being a wavelength of a wave generated by the surface acoustic wave device.
13. The surface acoustic wave device of claim 12 further including a functional layer below the piezoelectric layer and a support substrate layer below the functional layer.
14. An acoustic wave filter comprising:
a surface acoustic wave resonator configured to filter a radio frequency signal, the surface acoustic wave resonator including a piezoelectric layer, an interdigital transducer electrode including a pair of electrodes, each electrode having a bus bar and fingers extending from the bus bar, the interdigital transducer electrode having an interdigital region defined by a portion of the fingers of the electrodes that interdigitate with each other, a dielectric layer disposed over the interdigital transducer electrode outside the interdigital region and configured to reduce a loss of the surface acoustic wave resonator, and a functional layer below the piezoelectric layer and a support substrate layer below the functional layer, and the functional layer is a silicon dioxide layer.
15. The acoustic wave filter of claim 14 wherein the dielectric layer is a tantalum pentoxide layer.
16. The acoustic wave filter of claim 14 wherein the functional layer includes a first functional layer and a second functional layer, and the surface acoustic wave resonator further including a metal layer between the first functional layer and the second functional layer.
17. The acoustic wave filter of claim 14 wherein the dielectric layer is disposed over a dummy region and a gap region of the interdigital transducer electrode.
18. A wireless communication device comprising:
an antenna; and
a front end module including one or more surface acoustic wave resonators configured to filter a radio frequency signal associated with the antenna, each surface acoustic wave resonator including a piezoelectric layer, an interdigital transducer electrode including a pair of electrodes, each electrode having a bus bar and fingers extending from the bus bar, the interdigital transducer electrode having an interdigital region defined by a portion of the fingers of the electrodes that interdigitate with each other, and a dielectric layer disposed over the interdigital transducer electrode outside the interdigital region and configured to reduce a loss of the surface acoustic wave resonator, the dielectric layer having a thickness of between 0.01L and 0.04L, L being a wavelength of a wave generated by the one or more surface acoustic wave resonators.
19. The wireless communication device of claim 18 wherein the dielectric layer is a tantalum pentoxide layer.
20. The wireless communication device of claim 18 wherein the dielectric layer is disposed over a dummy region of the interdigital transducer electrode.