Bulk acoustic wave resonator having a plurality of compensation layers and duplexer using same

• US 9,735,754 B2
• Filed: 07/26/2012
• Issued: 08/15/2017
• Est. Priority Date: 07/27/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shin, Jea Shik, Song, In Sang, Kim, Young Il, Kim, Hyung Rak, Lee, Jae Chun, Kim, Duck Hwan, Kim, Chul Soo, Son, Sang Uk
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US13/558,907
• Publication Number:
  US 20130027153A1
• Time in Patent Office: 1,846 Days
• Field of Search: 333133, 333187-192, 310346
• CPC Class Codes: H03H 9/02102 of temperature influence cutting angles H03H9/02015
• CPC Class Codes: H03H 9/171 implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
• CPC Class Codes: H03H 9/173 Air-gaps
• CPC Class Codes: H03H 9/174 Membranes
• CPC Class Codes: H03H 9/588 Membranes
• CPC Class Codes: H03H 9/706 Duplexers

Abstract

A bulk acoustic wave resonator (BAWR) includes a bulk acoustic resonance unit and at least one compensation layer. The bulk acoustic resonance unit includes a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode. The first electrode, the second electrode, and the piezoelectric layer each include a material that modifies a resonance frequency based on a temperature, and the at least one compensation layer includes a material that adjusts the resonance frequency modified based on the temperature in a direction opposite to a direction of the modification.

Claims

1. A film bulk acoustic wave resonator (BAWR) comprising:

a substrate;

an air cavity disposed between the substrate and a bulk acoustic resonance unit;

the bulk acoustic resonance unit comprising;

a first electrode,

a second electrode, and

a piezoelectric layer disposed between the first electrode and the second electrode;

a plurality of compensation layers comprising respective materials that adjusts a resonance frequency that is modified in the bulk acoustic resonance unit according to a temperature; and

a property compensation layer included above the plurality of compensation layers,

wherein the first electrode is disposed above the piezoelectric layer and the second electrode is disposed below the piezoelectric layer,

wherein the plurality of compensation layers comprises;

a first compensation layer disposed above the first electrode;

a second compensation layer disposed below the second electrode; and

a third compensation layer disposed below the second electrode, and

wherein the property compensation layer is included above the edges of a surface of the first compensation layer so that a remaining portion of the surface between the edges is not covered by the property compensation layer.

2. The BAWR of claim 1, wherein the compensation layers adjust a temperature coefficient of the bulk acoustic wave resonance unit.

3. The BAWR of claim 1, wherein a sum of a thickness of each of the compensation layers is less than or equal to a sum of a thickness of the first electrode, a thickness of the piezoelectric layer, and a thickness of the second electrode.

4. The BAWR of claim 1, wherein a sum of a thickness of each of the compensation layers is less than or equal to 2 micrometers (μ

m).

5. The BAWR of claim 1, wherein the compensation layers comprise a silicon oxide-based material.

6. The BAWR of claim 1, wherein the compensation layers comprise a silicon nitride-based material.

7. The BAWR of claim 1, wherein the compensation layers comprise silicon oxide doped with an impurity.

8. The BAWR of claim 7, wherein the impurity comprises at least one element selected from the group consisting of arsenic (As), antimony (Sb), phosphorus (P), boron (B), germanium (Ge), silicon (Si), and aluminum (Al).

9. The BAWR of claim 1, wherein the compensation layers comprise silicon nitride doped with an impurity.

10. The BAWR of claim 9, wherein the impurity comprises at least one element selected from the group consisting of arsenic (As), antimony (Sb), phosphorus (P), boron (B), germanium (Ge), silicon (Si), and aluminum (Al).

11. The BAWR of claim 1, further comprising a membrane contacting the bulk acoustic resonance unit;

wherein the compensation layers comprise a compensation layer that is a portion of the membrane that has been doped with an impurity.

12. The BAWR of claim 1, wherein a sum of a temperature coefficient of frequency (TCF) of the bulk acoustic wave resonance unit and a TCF of the plurality of compensation layers is substantially zero.

13. The BAWR of claim 1, wherein each of the first electrode, the second electrode, and the piezoelectric layer comprises respective materials that modify the resonance frequency based on the temperature, and

wherein the respective materials of the plurality of compensation layers adjust the resonance frequency modified based on the temperature in a direction opposite to a direction of the modification by the first electrode, the second electrode, and the piezoelectric layer.

14. The BAWR of claim 1, wherein the plurality of compensation layers further comprises,

a fourth compensation layer disposed below the first compensation layer.

15. The BAWR of claim 1, wherein the first electrode abuts the piezoelectric layer, the piezoelectric layer abuts the second electrode, and the second electrode abuts the second compensation layer.

16. The BAWR of claim 1, wherein a portion of the third compensation layer abuts the air cavity.

17. The BAWR of claim 1, wherein a portion of the first electrode, above the air cavity, is thicker than another portion of first electrode, above the air cavity, to affect an acoustic wave reflection characteristic of the bulk acoustic resonance unit.

18. The BAWR of claim 1, wherein the property compensation layer comprises an electrically conductive metal element.

19. The BAWR of claim 18, wherein the metal element comprises Al.

20. The BAWR of claim 18, wherein the property compensation layer comprises a first material doped with the metal element.

21. The BAWR of claim 20, wherein the first material is a silicon oxide or silicon nitride material.

22. A film bulk acoustic wave resonator (BAWR) comprising:

a substrate;

an air cavity disposed below a second electrode;

a bulk acoustic wave resonance unit comprising;

a first electrode disposed so that the air cavity is between the first electrode and the substrate,

the second electrode disposed between the first electrode and the air cavity, and

a piezoelectric layer disposed between the first electrode and the second electrode;

a first compensation layer disposed above the first electrode;

a second compensation layer disposed below the second electrode; and

a third compensation layer disposed below the second electrode,

wherein the first compensation layer, the second compensation layer and the third compensation layer comprise a silicon nitride-based material.

23. The BAWR of claim 22, wherein a sum of a thickness of the first compensation layer and a thickness of the second compensation layer is less than or equal to a sum of a thickness of the first electrode, a thickness of the piezoelectric layer, and a thickness of the second electrode.

24. The BAWR of claim 22, comprising a fourth compensation layer disposed below the first compensation layer.

25. The BAWR of claim 22, wherein the first compensation layer, the second compensation layer and the third compensation layer comprise silicon nitride doped with an impurity.

26. The BAWR of claim 25, wherein the impurity comprises at least one element selected from the group consisting of arsenic (As), antimony (Sb), phosphorus (P), boron (B), germanium (Ge), silicon (Si), and aluminum (Al).

27. A duplexer comprising:

a first filter configured to filter a transmission signal received from a transmit input of the duplexer, and output the filtered transmission signal to an antenna;

a phase shifter configured to shift a phase of a received signal received from the antenna, and output the phase-shifted received signal; and

a second filter configured to filter the phase-shifted received signal output from the phase shifter, and output the filtered phase-shifted received signal to a receive output of the duplexer;

wherein the first filter and the second filter operate at different predetermined resonance frequencies,

wherein the phase shifter is further configured to shift the phase of the received signal to prevent signal interference between the first filter and the second filter,

wherein each of the first filter and the second filter comprises;

a film bulk acoustic source resonance unit, disposed above an air cavity, comprising;

a first electrode,

a second electrode, and

a piezoelectric layer;

a plurality of compensation layers comprising respective materials that adjusts a resonance frequency that is modified in the bulk acoustic source resonance unit based on a temperature in a direction opposite to a direction of the modification; and

a property compensation layer included above the plurality of compensation layers,

wherein the first electrode is disposed above the piezoelectric layer and the second electrode is disposed below the piezoelectric layer, and

wherein the plurality of compensation layers comprises;

a first compensation layer disposed above the first electrode;

a second compensation layer disposed below the second electrode; and

a third compensation layer disposed below the second electrode, and

wherein the property compensation layer is included above the edges of a surface of the first compensation layer so that a remaining portion of the surface between the edges is not covered by the property compensation layer.

28. The BAWR of claim 27, wherein the first compensation layer, the second compensation layer and the third compensation layer comprise a silicon oxide-based material.

29. The BAWR of claim 27, wherein the first compensation layer, the second compensation layer and the third compensation layer comprise silicon oxide doped with an impurity.

30. The BAWR of claim 29, wherein the impurity comprises at least one element selected from the group consisting of arsenic (As), antimony (Sb), phosphorus (P), boron (B), germanium (Ge), silicon (Si), and aluminum (Al).