Acoustic wave resonator RF filter circuit and system

Patent metadata

Field	Value
Publication number	US-11637545-B2
Application number	US-202217886171-A
Country	US
Kind code	B2
Filing date	Aug 11, 2022
Priority date	Mar 11, 2016
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

An RF filter system including a plurality of BAW resonators arranged in a circuit, the circuit including a serial configuration of resonators and a parallel shunt configuration of resonators, the circuit having a circuit response corresponding to the serial configuration and the parallel configuration of the plurality of bulk acoustic wave resonators including a transmission loss from a pass band having a bandwidth from 5.490 GHz to 5.835 GHz. Resonators include a support member with a multilayer reflector structure; a first electrode including tungsten; a piezoelectric film including aluminum scandium nitride; a second electrode including tungsten; and a passivation layer including silicon nitride. At least one resonator includes at least a portion of the first electrode located within a cavity region defined by a surface of the support member.

First claim

What is claimed is:

1. An RF filter system, comprising:
a plurality of bulk acoustic wave resonators arranged in a circuit, the circuit including a serial configuration of resonators and a parallel shunt configuration of resonators, the circuit having a circuit response corresponding to the serial configuration and the parallel configuration of the plurality of bulk acoustic wave resonators, each of the resonators of the plurality of resonators comprising:
a support member including a surface, the support member including a multilayer reflector structure including two pairs of a low impedance material layer and a high impedance material layer when the material layers are compared to each other;
a first electrode including tungsten overlying the multilayer reflector structure;
a piezoelectric film including aluminum scandium nitride overlapping the first electrode and overlying the multilayer reflector structure;
a second electrode including tungsten overlapping the piezoelectric film, overlapping the first electrode, and overlying the multilayer reflector; and
a passivation layer including silicon nitride overlying the second electrode; wherein,
portions of the surface of the support member of at least one resonator of the plurality of bulk acoustic wave resonators define a cavity region and at least a portion of the first electrode of the at least one resonator is located within the cavity region defined by the surface of the support member; and
the circuit response corresponding to the serial configuration and the parallel configuration of the plurality of resonators has a pass band having a bandwidth from 5.490 GHz to 5.835 GHz.

2. The system of claim 1 , the circuit having a circuit topology, wherein the serial configuration of resonators and the parallel shunt configuration of resonators are arranged in a ladder circuit topology having an insertion loss of ≤2.0 dB.

3. The system of claim 2 , further comprising:
at least one resonator of the plurality of bulk acoustic wave resonators including at least one trimmed material layer such that the pass band of the circuit has a bandwidth from 5.490 GHz to 5.835 GHz, the at least one trimmed material layer including at least one of the passivation layer and the second electrode having a thickness sufficient to provide the pass band having a bandwidth from 5.490 GHz to 5.835 GHz.

4. The system of claim 3 , wherein,
the at least one resonator of the plurality of bulk acoustic wave resonators including at least a portion of the first electrode located in the cavity region defined by the surface of the support member, and
the at least one resonator of the plurality of bulk acoustic wave resonators including at least one trimmed material layer,
are the same resonator.

5. The system of claim 1 , further comprising:
a mass loaded structure overlying the second electrode, wherein the passivation layer including silicon nitride overlies the mass loaded structure.

6. The system of claim 5 , further comprising:
at least one resonator of the plurality of bulk acoustic wave resonators including:
an electrode contact via through the piezoelectric film; and
a top metal physically coupled to the first electrode through the electrode contact via.

7. An RF filter system, comprising:
a plurality of bulk acoustic wave resonators arranged in a circuit, the circuit including a serial configuration of resonators and a parallel shunt configuration of resonators, the circuit having a circuit response corresponding to the serial configuration and the parallel configuration of the plurality of bulk acoustic wave resonators, each of the resonators of the plurality of resonators comprising:
a support member including a surface, the support member including a multilayer reflector structure including two pairs of a low impedance material layer and a high impedance material layer when the material layers are compared to each other;
a first electrode including tungsten overlying the multilayer reflector structure;
a piezoelectric film including aluminum scandium nitride overlapping the first electrode and overlying the multilayer reflector structure;
a second electrode including tungsten overlapping the piezoelectric film, overlapping the first electrode, and overlying the multilayer reflector, a resonator area being defined by an area where the second electrode, the piezoelectric film, and the first electrode overlap;
a passivation layer including silicon nitride overlying the second electrode; wherein,
portions of the surface of the support member of at least one resonator of the plurality of bulk acoustic wave resonators define a cavity region and at least a portion of the first electrode of the at least one resonator is located within the cavity region defined by the surface of the support member; and
the circuit response corresponding to the serial configuration and the parallel configuration of the plurality of resonators has a pass band having a bandwidth from 5.490 GHz to 5.835 GHz;
at least one resonator of the plurality of bulk acoustic wave resonators includes at least one trimmed material layer such that the pass band of the circuit has a bandwidth from 5.490 to 5.835 GHz, wherein the at least one trimmed material layer includes a first thickness in the resonator area that is thinner than a second thickness in another area of the same material layer such that the pass band of the circuit has a bandwidth from about 5.490 to 5.835 GHz.

8. The system of claim 7 , wherein,
the at least one resonator of the plurality of bulk acoustic wave resonators including at least a portion of the first electrode located within the cavity region defined by the surface of the support member, and
the at least one resonator of the plurality of bulk acoustic wave resonators including at least one trimmed material layer,
are the same resonator.

9. The system of claim 8 , further comprising:
a mass loaded structure overlying the second electrode, wherein the passivation layer including silicon nitride overlies the mass loaded structure.

10. The system of claim 9 , the circuit having a circuit topology, wherein the serial configuration of resonators and the parallel shunt configuration of resonators are arranged in a ladder circuit topology having an insertion loss of ≤2.0 dB.

11. The system of claim 10 further comprising:
at least one resonator of the plurality of bulk acoustic wave resonators arranged in the circuit including:
an electrode contact via through the piezoelectric film; and
a top metal physically coupled to the first electrode through the electrode contact via.

12. The system of claim 1 , a resonator area being defined by an area where the second electrode, the piezoelectric film, and the first electrode overlap, the system further comprising:
a mass loaded structure overlying the second electrode, wherein the mass loaded structure is located outside of the resonator area.

13. The system of claim 12 , wherein the mass loaded structure surrounds the resonator area.

14. The system of claim 12 , the circuit having a circuit topology, wherein the serial configuration of resonators and the parallel shunt configuration of resonators are arranged in a ladder circuit topology having an insertion loss of ≤2.0 dB.

15. The system of claim 1 , wherein the piezoelectric film including aluminum scandium nitride is one of a single crystal material and a polycrystalline material.

16. The system of claim 1 , wherein
the first electrode is located within the cavity region defined by the surface of the support member such that the surface of the suppo

Assignees

• Akoustis Inc

Inventors

• Shealy Jeffrey B
• Hodge Michael
• Houlden Rohan W
• Gibb Shawn R
• Winters Mary
• Vetury Ramakrishna
• Aichele David M

Classifications

• H03H9/581

  comprising ceramic piezoelectric layers · CPC title

• H03H9/0533

  consisting of wire · CPC title

• H03H2003/021

  the resonators or networks being of the air-gap type · CPC title

• H03H9/02031

  consisting of ceramic · CPC title

• H03H9/1035

  the enclosure being defined by two sealing substrates sandwiching the piezoelectric layer of the BAW device · CPC title