Acoustic resonator and method of manufacturing the same
An acoustic resonator and a method of manufacturing the same are provided. The acoustic resonator includes a resonating part including a first electrode, a second electrode, and a piezoelectric layer; and a plurality of seed layers disposed on one side of the resonating part.
1. An acoustic resonator comprising:
a resonating part comprising a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode; and
a plurality of seed layers disposed on one side of the resonating part,
wherein the plurality of seed layers comprise a first seed layer and a second seed layer,
wherein an upper surface of the second seed layer corresponds to a (002) plane of hexagonal lattice.
2. The acoustic resonator of claim 1 , further comprising a substrate disposed on the opposite side of the plurality of seed layers from the resonating part.
3. The acoustic resonator of claim 2 , wherein an air gap is disposed between the substrate and the plurality of seed layers.
4. The acoustic resonator of claim 2 , wherein the resonating part further comprises a protection layer.
5. The acoustic resonator of claim 2 , wherein a membrane is interposed between the substrate and the plurality of seed layers, and
an air gap is disposed between the substrate and the membrane.
6. The acoustic resonator of claim 5 , wherein the membrane comprises a plurality of membrane layers, and
at least one membrane layer of the plurality of membrane layers is an etching stopper.
7. The acoustic resonator of claim 1 , wherein
the first seed layer comprises a material having the same crystalline system as a material of the piezoelectric layer, and
wherein the second seed layer comprises a material having the same unit cell geometry as a material of the first seed layer.
8. The acoustic resonator of claim 7 , wherein a thickness of the first seed layer or the second seed layer is within a range of 10 Å to 1,000 Å.
9. The acoustic resonator of claim 7 , wherein the piezoelectric layer, the first seed layer, and the second seed layer each comprise a material having a hexagonal crystal system.
10. The acoustic resonator of claim 9 , wherein the second seed layer comprises a material having a hexagonal close packed structure.
11. The acoustic resonator of claim 9 , wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum,
the first seed layer comprises aluminum nitride, and
the second seed layer comprises titanium.
12. The acoustic resonator of claim 1 , wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum,
the first seed layer comprises titanium, and
the second seed layer comprises aluminum nitride.
13. An acoustic resonator comprising:
a resonating part comprising a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode; and
a plurality of seed layers disposed on one side of the resonating part,
wherein a first seed layer and a second seed layer of the plurality of seed layers, and the piezoelectric layer each comprise a material having a hexagonal crystal system.
14. The acoustic resonator of claim 13 , wherein the second seed layer comprises a material having a hexagonal close packed structure.
15. The acoustic resonator of claim 13 , wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum,
the first seed layer comprises aluminum nitride, and
the second seed layer comprises titanium.
16. The acoustic resonator of claim 13 , wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum,
the first seed layer comprises titanium, and
the second seed layer comprises aluminum nitride.
17. An acoustic resonator comprising:
a resonating part comprising a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode;
a plurality of seed layers disposed on one side of the resonating part, comprising a first seed layer and a second seed layer;
a substrate disposed on the opposite side of the plurality of seed layers from the resonating part; and
a plurality of membrane layers interposed between the substrate and the plurality of seed layers,
wherein a lattice mismatch between the first seed layer and the second seed layer is less than or equal to 12.45%.