Thin film bulk acoustic resonator ( FBAR) and inductor on a monolithic substrate and method of fabricating the same

• US 20030009863A1
• Filed: 07/13/2001
• Published: 01/16/2003
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Bradley, Paul, Figueredo, Domingo A., Ruby, Richard C., Oshmyansky, Yury
• Granted Patent: US 6,710,681 B2
• Time in Patent Office: Days
• US Class Current: 29/25.35
• CPC Class Codes: H03H 9/0542 consisting of a lateral arrangement H03H9/0566 takes precedence
• CPC Class Codes: H03H 9/542 including passive elements H03H9/545 takes precedence
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

An apparatus having both a resonator and an inductor fabricated on a single substrate and a method of fabricating the apparatus are disclosed. The apparatus includes a resonator and an inductor that is connected to the resonator. Both the resonator and the inductor are fabricated over their respective cavities to produce a high Q-factor filter circuit.

Claims

1. An apparatus comprising:

a resonator fabricated on a substrate bridging a first cavity; and

an inductor fabricated on the substrate bridging a second cavity, the inductor connected to the resonator.

2. The apparatus recited in claim 1 wherein the resonator is a thin film bulk acoustic resonator.

3. The apparatus recited in claim 1 wherein the resonator comprises a piezoelectric (PZ) layer sandwiched between two electrodes.

4. The apparatus recited in claim 3 wherein the PZ layer comprises Aluminum Nitride (AlN).

5. The apparatus recited in claim 1 wherein the resonator comprises Aluminum Nitride (AlN) layer.

6. The apparatus recited in claim 1 wherein the resonator comprises Molybdenum.

7. The apparatus recited in claim 1 wherein the inductor comprises Molybdenum.

8. An electronic filter comprising:

a resonator fabricated on a substrate bridging a first cavity; and

an inductor fabricated on the substrate bridging a second cavity, the inductor connected to the resonator.

9. The electronic filter recited in claim 8 wherein the resonator is a thin film bulk acoustic resonator.

10. The electronic filter recited in claim 8 wherein the resonator comprises a piezoelectric (PZ) layer sandwiched between two electrodes.

11. The electronic filter recited in claim 10 wherein the PZ layer comprises Aluminum Nitride (AlN).

12. The electronic filter recited in claim 8 wherein the resonator bridges a cavity.

13. The electronic filter recited in claim 8 wherein the resonator comprises Aluminum Nitride (AlN) layer.

14. The electronic filter recited in claim 8 wherein the resonator comprises Molybdenum.

16. The method recited in claim 15 wherein the step of fabricating the resonator comprising:

fabricating a bottom electrode layer;

fabricating a piezoelectric (PZ) layer over the bottom electrode layer; and

fabricating a top electrode over the PZ layer.

17. A method recited in claim 16 wherein the PZ layer comprises Aluminum Nitride (AlN).

18. A method recited in claim 16 wherein the top electrode comprises Molybdenum.

19. A method recited in claim 15 wherein the step of fabricating the inductor comprises:

fabricating a cavity within the substrate; and

fabricating the inductor bridging the cavity.

15. A method of fabricating an electronic filter on a substrate, the method comprising:

fabricating a resonator on the substrate; and

fabricating an inductor, connected to the resonator, on the substrate.

20. A method of fabricating an electronic filter on a substrate, the method comprising:

fabricating a cavity within the substrate;

filling the cavity with sacrificial material;

fabricating an inductor above the cavity; and

removing the sacrificial material from the cavity.