Acoustic wave device with acoustic obstruction structure
An acoustic wave device is disclosed. The acoustic wave device can include a support substrate that includes a first substrate portion, a second substrate portion, and a third substrate portion between the first substrate portion and the second substrate portion. The acoustic wave device can include a piezoelectric layer that includes a first portion over the first substrate portion and a second portion over the second substrate portion. The piezoelectric layer can be arranged such that a region over the third substrate portion is free from the piezoelectric layer. The acoustic wave device can include a filter circuit formed on the first portion of the piezoelectric layer. The acoustic wave device can include a cancelation circuit on the second portion of the piezoelectric layer.
1. An acoustic wave device comprising:
a support substrate including a first substrate portion, a second substrate portion, and a third substrate portion between the first substrate portion and the second substrate portion;
a piezoelectric layer including a first portion over the first substrate portion and a second portion over the second substrate portion, a filter circuit formed on the first portion of the piezoelectric layer, a cancelation circuit formed on the second portion of the piezoelectric layer;
patterned metal formed on the piezoelectric layer between the filter circuit and the cancelation circuit; and
an acoustic obstruction structure disposed laterally between the first portion and the second portion of the piezoelectric layer, the acoustic obstruction structure configured to reduce acoustic coupling between the filter circuit and the cancelation circuit.
2. The acoustic wave device of claim 1 wherein the acoustic obstruction structure includes a gap between the first portion of the piezoelectric layer and the second portion of the piezoelectric layer that is free from the piezoelectric layer.
3. The acoustic wave device of claim 1 wherein the acoustic obstruction structure includes a polymer wall.
4. The acoustic wave device of claim 1 wherein the acoustic obstruction structure is positioned between a resonator of the filter circuit and a resonator of the cancelation circuit.
5. The acoustic wave device of claim 1 wherein the filter circuit includes a first filter portion and a second filter portion, the first filter portion formed mainly of ladder filters.
6. The acoustic wave device of claim 5 wherein the second filter portion includes a multi-mode longitudinally coupled surface acoustic wave resonator.
7. The acoustic wave device of claim 1 further comprising an intermediate layer between the support substrate and the piezoelectric layer.
8. The acoustic wave device of claim 7 wherein the intermediate layer includes a first intermediate layer portion over the first substrate portion and a second Intermediate layer portion over the second substrate portion, the acoustic obstruction structure is disposed between the first intermediate layer portion and the second intermediate layer portion.
9. An acoustic wave device comprising:
a support substrate including a first substrate portion, a second substrate portion, and a third substrate portion between the first substrate portion and the second substrate portion;
a piezoelectric layer including a first portion over the first substrate portion and a second portion over the second substrate portion, the piezoelectric layer arranged such that a region over the third substrate portion is free from the piezoelectric layer;
a filter circuit formed on the first portion of the piezoelectric layer; and
a cancelation circuit formed on the second portion of the piezoelectric layer; and
patterned metal formed on the piezoelectric layer between the filter circuit and the cancelation circuit.
10. The acoustic wave device of claim 9 wherein an etched portion of the piezoelectric layer defines the region over the third substrate portion that is free from the piezoelectric layer.
11. The acoustic wave device of claim 9 wherein the cancelation circuit is positioned in a longitudinal direction of a resonator of the filter circuit.
12. The acoustic wave device of claim 9 wherein the cancelation circuit is positioned in an acoustic propagation direction of a resonator of the filter circuit.
13. The acoustic wave device of claim 9 further comprising an intermediate layer between the support substrate and the piezoelectric layer.
14. The acoustic wave device of claim 13 wherein the intermediate layer includes a first intermediate layer portion and a second intermediate layer portion under the first portion of the piezoelectric layer and the second portion of the piezoelectric layer respectively.
15. The acoustic wave device of claim 14 wherein the region over the third substrate portion that is free from the piezoelectric layer is free from the intermediate layer.
16. The acoustic wave device of claim 9 further comprising an acoustic obstacle in the region over the third substrate portion, wherein the acoustic obstacle is arranged to absorb acoustic energy.
17. The acoustic wave device of claim 16 wherein the acoustic obstacle includes a polymer wall.
18. The acoustic wave device of claim 9 wherein the patterned metal is formed on the first portion of the piezoelectric layer and the second portion of the piezoelectric layer between the filter circuit and the cancelation circuit.
19. The acoustic wave device of claim 9 wherein edges of the first portion of the piezoelectric layer have non-straight edges.
20. The acoustic wave device of claim 9 wherein a resonator of the filter circuit is tilted.