Resonators with balancing capacitor
View Patent ↗Embodiments provide a solidly-mounted bulk acoustic wave (BAW) resonator and method of making same. In embodiments, the BAW resonator may include a first resonator and a second resonator that are coupled with one another via a top electrode layer. A capacitive element may be included in the BAW resonator in parallel with the first resonator. Other embodiments may be described and claimed.
1. A bulk acoustic wave (BAW) resonator comprising:
a first resonator that includes a first top electrode and a first bottom electrode;
a second resonator that includes a second top electrode coupled with the first top electrode and a second bottom electrode;
a parasitic capacitive structure coupled with the first and second top electrodes and positioned between the first and second top electrodes and a ground; and
a balancing capacitive structure coupled with the first top electrode and the first bottom electrode.
2. The BAW resonator of claim 1 , wherein a capacitance of the balancing capacitive structure is smaller than a capacitance of the first resonator.
3. The BAW resonator of claim 1 , wherein a load impedance of the balancing capacitive structure is based on a load impedance of the first resonator, a load impedance of the second resonator, a load impedance of the parasitic capacitive structure, and a load impedance of a load coupled to the second bottom electrode and positioned between the second bottom electrode and the ground.
4. The BAW resonator of claim 3 , wherein the load impedance of the balancing capacitive structure is Z Balancing and
Z
Balancing
=
Z
Resonator
1
*
Z
Parasitic
Z
Resonator
2
+
Z
Load
wherein Z Resonator1 is the load impedance of the first resonator, Z parasitic is the load impedance of the parasitic capacitive structure, Z Resonator2 is the load impedance of the second resonator, and Z Load is the load impedance of the load.
5. The BAW resonator of claim 1 , wherein the balancing capacitive structure includes a metal positioned within the BAW resonator to cause a capacitive effect between the metal and the top electrode.
6. The BAW resonator of claim 5 , wherein the metal is Tungsten (W).
7. The BAW resonator of claim 1 , wherein the first resonator and the second resonator include a piezoelectric layer and a reflective layer that includes a reflective metal.
8. The BAW resonator of claim 7 , wherein the piezoelectric layer includes Aluminum Nitride (AlN).
9. The BAW resonator of claim 1 , wherein the top electrode, the first bottom electrode, or the second bottom electrode include an Aluminum-Copper compound (AlCu) or Tungsten (W).
10. A bulk acoustic wave (BAW) resonator comprising:
a first resonator that includes a piezoelectric layer between a first electrode and a second electrode, and a reflective layer having a first mirror metal;
a second resonator that includes the piezoelectric layer between the first electrode and a third electrode, and the reflective layer having a second mirror metal; and
a capacitive element positioned such that a capacitive effect is formed between the first electrode and the capacitive element, wherein the capacitive element is separate from, but co-planar with the first mirror metal.
11. The BAW resonator of claim 10 , wherein a capacitive effect is further formed between the second electrode and the capacitive element.
12. The BAW resonator of claim 10 , wherein the capacitive element includes Tungsten (W).
13. The BAW resonator of claim 10 , wherein the reflective layer further includes Silicon Oxide (SiO 2 ).
14. The BAW resonator of claim 10 , wherein the first or second mirror metal are Tungsten (W).
15. The BAW resonator of claim 10 , wherein the capacitive element is physically coupled with the second electrode.
16. The BAW resonator of claim 10 , wherein the first electrode, second electrode, or third electrode include an Aluminum-Copper compound (AlCu) or Tungsten (W).
17. The BAW resonator of claim 10 , wherein the piezoelectric layer includes Aluminum Nitride (AlN).
18. The BAW resonator of claim 10 , wherein the first electrode is a top electrode, the second electrode is a first bottom electrode, and the third electrode is a second bottom electrode; and
wherein the reflective layer is coupled with the first bottom electrode on a side of the first bottom electrode opposite a side of the first bottom electrode that is coupled with the piezoelectric layer.
19. The BAW resonator of claim 10 , wherein the first electrode is a bottom electrode, the second electrode is a top electrode, and the third electrode is a second top electrode; and
wherein the reflective layer is coupled with the bottom electrode on a side of the bottom electrode opposite a side of the bottom electrode that is coupled with the piezoelectric layer.