Granted Patent B2

US 9,065,421 · App. 13/362,321 · Granted Jun 23, 2015

Abstract

Claims (27)

1. An acoustic resonator, comprising:

a first electrode;

a second electrode;

a first piezoelectric layer and a second piezoelectric layer between the first and second electrodes, the first and second piezoelectric layers being comprised of respective different piezoelectric materials;

a third electrode between the first and second piezoelectric layers; and

a third piezoelectric layer laminated to the first piezoelectric layer, the third piezoelectric layer comprising a piezoelectric material different than the piezoelectric material of the first piezoelectric layer.

2. The acoustic resonator of claim 1 , wherein a c-axis orientation of the first piezoelectric layer is the same as a c-axis orientation of the second piezoelectric layer.

3. The acoustic resonator of claim 1 , wherein a c-axis orientation of the first piezoelectric layer is opposite a c-axis orientation of the second piezoelectric layer.

4. The acoustic resonator of claim 1 , wherein the first piezoelectric layer comprises AlN and the second piezoelectric layer comprises ZnO.

5. The acoustic resonator of claim 4 , wherein the first and second electrodes are comprised of W or Mo.

6. The acoustic resonator of claim 1 , wherein the first and second electrodes are electrically connected to each other.

7. The acoustic resonator of claim 1 , further comprising a fourth piezoelectric layer laminated to the second piezoelectric layer, the fourth piezoelectric layer comprising a piezoelectric material different than the piezoelectric material of the second piezoelectric layer.

8. The acoustic resonator of claim 7 , wherein a c-axis orientation of the fourth piezoelectric layer is the same as a c-axis orientation of the second piezoelectric layer.

9. The acoustic resonator of claim 7 , wherein a c-axis orientation of the fourth piezoelectric layer is opposite a c-axis orientation of the second piezoelectric layer.

10. The acoustic resonator of claim 1 , having a resonance frequency set based on respective c-axis orientations of the first and second piezoelectric layers.

11. The acoustic resonator of claim 1 , wherein a c-axis orientation of the third piezoelectric layer is opposite a c-axis orientation of the first piezoelectric layer.

12. The acoustic resonator of claim 1 , wherein a c-axis orientation of the third piezoelectric layer is the same as a c-axis orientation of the first piezoelectric layer.

13. A method of making an acoustic resonator, the method comprising:

forming a first piezoelectric layer having a first c-axis orientation on first electrode;

forming a second piezoelectric layer having a second c-axis orientation over the first piezoelectric layer,

the first and second piezoelectric layers comprised of respective different piezoelectric materials;

selecting the second c-axis orientation during formation of the second piezoelectric layer to set a resonance frequency of the acoustic resonator; and

forming a second electrode on the second piezoelectric layer;

forming a third electrode between the first and second piezoelectric layers;

electrically connecting the first and second electrodes together; and

laminating a third piezoelectric layer to the first piezoelectric layer, the third piezoelectric layer comprising a piezoelectric material different than a piezoelectric material of the first piezoelectric layer, wherein the first and second c-axis orientations are selected to be the same to set a first resonance frequency and are selected to be opposite to set a different second resonance frequency.

14. The method of claim 13 , thither comprising laminating a fourth piezoelectric layer to the second piezoelectric layer, the fourth piezoelectric layer comprising a piezoelectric material different than a piezoelectric material of the second piezoelectric layer.

Assignments (8)