Filter with bulk acoustic wave device having raised frame structure
A filter with bulk acoustic wave devices is disclosed. The filter includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. The first bulk acoustic wave resonator includes a first raised frame structure. The first raised frame structure is a multi-layer raised frame structure. The second bulk acoustic wave resonator includes a second raised frame structure. The first raised frame structure has at least one more raised frame layer than the second raised frame structure.
1. A filter with bulk acoustic wave devices, the filter comprising:
a first bulk acoustic wave resonator including a first raised frame structure within an active region, the first raised frame structure being a multi-layer raised frame structure having a multi-gradient raised frame structure; and
a second bulk acoustic wave resonator including a second raised frame structure within the active region, the first raised frame structure having at least one more raised frame layer than the second raised frame structure, the first and second raised frame structures increase reflection of lateral energy within the active region.
2. The filter of claim 1 wherein the second raised frame structure is a single layer raised frame structure.
3. The filter of claim 1 wherein the first raised frame structure has a first mass loading and the second raised frame structure has a second mass loading region that is less than the first mass loading.
4. The filter of claim 1 wherein the first bulk acoustic wave resonator includes a first electrode, a second electrode, and a piezoelectric layer positioned between the first electrode and the second electrode; the first raised frame structure including a first layer positioned between the second electrode and the piezoelectric layer.
5. The filter of claim 4 wherein a second layer of the first raised frame structure is positioned over the second electrode such that the second electrode is positioned between the first layer and the second layer, and the first layer includes an oxide and the second layer includes a metal.
6. The filter of claim 4 wherein the first layer has a lower acoustic impedance than the piezoelectric layer.
7. The filter of claim 1 wherein the filter is a band pass filter.
8. The filter of claim 7 wherein the first bulk acoustic wave resonator is a shunt resonator and the second bulk acoustic wave resonator is a series resonator.
9. The filter of claim 8 further comprising a plurality of shunt bulk acoustic wave resonators including the first bulk acoustic wave resonator, and a plurality of series resonators coupled to the second bulk acoustic wave resonator.
10. The filter of claim 1 wherein the filter is a band rejection filter.
11. The filter of claim 10 wherein the first bulk acoustic wave resonator is a series resonator and the second bulk acoustic wave resonator is a shunt resonator.
12. The filter of claim 11 further comprises a plurality of series bulk acoustic wave resonators including the first bulk acoustic wave resonator, and a plurality of shunt resonators coupled to the second bulk acoustic wave resonator.
13. The filter of claim 1 wherein the first raised frame structure includes an oxide layer that is in contact with a piezoelectric layer of the first bulk acoustic wave resonator, and the second raised frame structure does not include a further oxide layer that is in contact with a piezoelectric layer in an active region of the second bulk acoustic wave resonator.
14. The filter of claim 1 wherein the first bulk acoustic wave resonator includes a recessed frame structure between a main acoustically active region and the first raised frame structure.
15. The filter of claim 1 wherein the second bulk acoustic wave resonator includes a recessed frame structure between a main acoustically active region and the second raised frame structure.
16. A radio frequency module comprising:
a filter comprising:
a first bulk acoustic wave resonator including a first raised frame structure, the first raised frame structure being a multi-layer raised frame structure; and
a second bulk acoustic wave resonator including a second raised frame structure, the first raised frame structure having at least one more raised frame layer than the second raised frame structure; and
a radio frequency circuit element coupled to the filter, the filter and the radio frequency circuit element being enclosed within a common package.
17. The radio frequency module of claim 16 wherein the radio frequency circuit element is a radio frequency amplifier arranged to amplify a radio frequency signal.
18. The radio frequency module of claim 16 wherein the radio frequency circuit element is a switch configured to selectively couple the filter to an antenna port of the radio frequency module.
19. A wireless communication device comprising:
a filter comprising:
a first bulk acoustic wave resonator including a first raised frame structure, the first raised frame structure being a multi-layer raised frame structure; and
a second bulk acoustic wave resonator including a second raised frame structure, the first raised frame structure having at least one more raised frame layer than the second raised frame structure;
an antenna operatively coupled to the filter;
a radio frequency amplifier operatively coupled to the filter and configured to amplify a radio frequency signal; and
a transceiver in communication with the radio frequency amplifier.
20. The wireless communications device of claim 19 wherein the filter is a band pass filter or a band rejection filter, wherein, when the filter is the band pass filter, the first bulk acoustic wave resonator is a shunt resonator and the second bulk acoustic wave resonator is a series resonator, and wherein, when the filter is the band rejection filter, the first bulk acoustic wave resonator is a series resonator and the second bulk acoustic wave resonator is a shunt resonator.