Enhanced MEMS vibrating device

• US 9,998,088 B2
• Filed: 05/04/2015
• Issued: 06/12/2018
• Est. Priority Date: 05/02/2014
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Inventors: Bhattacharjee, Kushal, Zhgoon, Sergei
• Primary Examiner(s): Dougherty, Thomas
• Application Number:
  US14/703,060
• Publication Number:
  US 20150318838A1
• Time in Patent Office: 1,135 Days
• Field of Search: 310313 A, 310313 B, 310313 C, 310313 D, 310313 R, 310348, 310365, 333193
• CPC Class Codes: H03H 2009/155 using MEMS techniques
• CPC Class Codes: H03H 2009/241 Bulk-mode MEMS resonators
• CPC Class Codes: H03H 9/02228 Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer
• CPC Class Codes: H03H 9/02338 Suspension means
• CPC Class Codes: H03H 9/172 Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume

Abstract

A MEMS vibrating device includes a substrate, at least one anchor on a surface of the substrate, and a vibrating body suspended over the substrate by the at least one anchor. The vibrating body includes a first piezoelectric thin-film layer, a second piezoelectric thin-film layer over the first piezoelectric thin-film layer, and an inter-digital transducer embedded between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer. Embedding the inter-digital transducer between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer may result in enhanced vibrational characteristics of the MEMS vibrating device, thereby increasing the performance thereof.

Claims

1. A micro-electrical-mechanical system (MEMS) device comprising:

a substrate;

at least one anchor on a surface of the substrate; and

a vibrating body suspended over the substrate by the at least one anchor and comprising;

a first piezoelectric thin-film layer;

a second piezoelectric thin-film layer over the first piezoelectric thin-film layer; and

an inter-digital transducer embedded between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer and comprising a first electrode and a second electrode each having a number of interlocking conductive sections;

wherein a polarization of the first piezoelectric thin-film layer is parallel to a polarization of the second piezoelectric thin-film layer.

2. The MEMS device of claim 1 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are parallel to the surface of the substrate.

3. The MEMS device of claim 1 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are perpendicular to the surface of the substrate.

4. The MEMS device of claim 1 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are oblique to the surface of the substrate.

5. The MEMS device of claim 1 further comprising a functional layer over a surface of the first piezoelectric thin-film layer facing the substrate.

6. The MEMS device of claim 5 further comprising an additional functional layer over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

7. The MEMS device of claim 1 further comprising a functional layer over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

8. A micro-electrical-mechanical system (MEMS) device comprising:

a substrate;

at least one anchor on a surface of the substrate; and

a vibrating body suspended over the substrate by the at least one anchor and comprising;

a first piezoelectric thin-film layer;

a second piezoelectric thin-film layer over the first piezoelectric thin-film layer; and

an inter-digital transducer embedded between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer and comprising a first electrode and a second electrode each having a number of interlocking conductive sections;

wherein a polarization of the first piezoelectric thin-film layer is opposite to a polarization of the second piezoelectric thin-film layer.

9. The MEMS device of claim 8 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are parallel to the surface of the substrate.

10. The MEMS device of claim 8 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are perpendicular to the surface of the substrate.

11. The MEMS device of claim 8 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are oblique to the surface of the substrate.

12. The MEMS device of claim 8 further comprising a functional layer over a surface of the first piezoelectric thin-film layer facing the substrate.

13. The MEMS device of claim 12 further comprising an additional functional layer over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

14. The MEMS device of claim 8 further comprising a functional layer over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

15. A micro-electrical-mechanical system (MEMS) device comprising:

a substrate;

at least one anchor on a surface of the substrate; and

a vibrating body suspended over the substrate by the at least one anchor and comprising;

a first piezoelectric thin-film layer;

a second piezoelectric thin-film layer over the first piezoelectric thin-film layer; and

an inter-digital transducer embedded between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer and comprising a first electrode and a second electrode each having a number of interlocking conductive sections;

wherein a polarization of the first piezoelectric thin-film layer is oblique with respect to a polarization of the second piezoelectric thin-film layer.

16. The MEMS device of claim 15 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are oblique to the surface of the substrate.

17. The MEMS device of claim 15 further comprising a functional layer over a surface of the first piezoelectric thin-film layer facing the substrate.

18. The MEMS device of claim 17 further comprising an additional functional layer over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

19. The MEMS device of claim 15 further comprising a functional layer over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

20. A micro-electrical-mechanical system (MEMS) device comprising:

a substrate;

at least one anchor on a surface of the substrate; and

a vibrating body suspended over the substrate by the at least one anchor and comprising;

a first piezoelectric thin-film layer;

a second piezoelectric thin-film layer over the first piezoelectric thin-film layer;

an inter-digital transducer embedded between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer and comprising a first electrode and a second electrode each having a number of interlocking conductive sections;

a third electrode over a surface of the first piezoelectric thin-film layer facing the substrate; and

a fourth electrode over a surface of the second piezoelectric thin-film layer opposite the first piezoelectric thin-film layer.

21. The MEMS device of claim 20 wherein a polarization of the first piezoelectric thin-film layer is parallel to a polarization of the second piezoelectric thin-film layer.

22. The MEMS device of claim 21 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are parallel to the surface of the substrate.

23. The MEMS device of claim 21 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are perpendicular to the surface of the substrate.

24. The MEMS device of claim 21 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are oblique to the surface of the substrate.

25. The MEMS device of claim 20 wherein a polarization of the first piezoelectric thin-film layer is opposite to a polarization of the second piezoelectric thin-film layer.

26. The MEMS device of claim 25 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are parallel to the surface of the substrate.

27. The MEMS device of claim 25 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are perpendicular to the surface of the substrate.

28. The MEMS device of claim 25 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are oblique to the surface of the substrate.

29. The MEMS device of claim 20 wherein a polarization of the first piezoelectric thin-film layer is oblique with respect to a polarization of the second piezoelectric thin-film layer.

30. The MEMS device of claim 29 wherein the polarization of the first piezoelectric thin-film layer and the polarization of the second piezoelectric thin-film layer are oblique to the surface of the substrate.

31. The MEMS device of claim 20 further comprising a functional layer over a surface of the first conductive layer opposite the first piezoelectric thin-film layer.

32. The MEMS device of claim 31 further comprising an additional functional layer over a surface of the second conductive layer opposite the second piezoelectric thin-film layer.

33. The MEMS device of claim 20 further comprising a functional layer over a surface of the second conductive layer opposite the second piezoelectric thin-film layer.

34. A micro-electrical-mechanical system (MEMS) device comprising:

a substrate;

at least one anchor on a surface of the substrate; and

a vibrating body suspended over the substrate by the at least one anchor and comprising;

a first piezoelectric thin-film layer;

a second piezoelectric thin-film layer over the first piezoelectric thin-film layer;

an interposer layer between the first piezoelectric thin-film layer and the second piezoelectric thin-film layer; and

an inter-digital transducer embedded in the interposer layer and comprising a first electrode and a second electrode each having a number of interlocking conductive sections.