INTEGRATION OF PIEZOELECTRIC MATERIALS WITH SUBSTRATES

• US 20100301703A1
• Filed: 03/31/2010
• Published: 12/02/2010
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Sand9, Inc.
• Inventors: Kuypers, Jan H., Zolfagharkhani, Guiti, Gaidarzhy, Alexei, Chen, David M.
• Granted Patent: US 8,766,512 B2
• Time in Patent Office: Days
• US Class Current: 310/318
• CPC Class Codes: H03H 3/007 for the manufacture of electromechanical resonators or networks
• CPC Class Codes: H03H 9/02007 of bulk acoustic wave devices
• CPC Class Codes: H03H 9/02244 of microelectro-mechanical resonators
• CPC Class Codes: H03H 9/02535 of surface acoustic wave devices
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

Devices having piezoelectric material structures integrated with substrates are described. Fabrication techniques for forming such devices are also described. The fabrication may include bonding a piezoelectric material wafer to a substrate of a differing material. A structure, such as a resonator, may then be formed from the piezoelectric material wafer.

Claims

1. A device comprising:

a substrate comprising a first material;

a mechanical resonator comprising a piezoelectric material, different from the first material,

wherein the mechanical resonator is integrated with the substrate.

2. The device of claim 1, wherein the piezoelectric material is a single crystal piezoelectric material.

3. The device of claim 2, wherein the single crystal piezoelectric material is quartz.

4. The device of claim 3, wherein the first material is silicon.

5. The device of claim 1, wherein the mechanical resonator is suspended above the substrate.

6. The device of claim 5, wherein the substrate has a cavity formed therein, and wherein the mechanical resonator is suspended above the cavity.

7. The device of claim 1, wherein the piezoelectric material is chosen from the group consisting of:

aluminum nitride (AlN), zinc oxide (ZnO), cadmium sulfide (CdS), lead titanate (PbTiO3), lead zirconate titanate (PZT), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), potassium niobate (KNbO3), Li2B4O7, langasite (La3Ga5SiO14), gallium arsenside (GaAs), barium sodium niobate, bismuth germanium oxide, indium arsenide, and indium antimonide.

8. The device of claim 1, further comprising a cap bonded to the substrate to form a hermetically sealed environment for the mechanical resonator.

9. The device of claim 8, further comprising integrated circuitry formed on the substrate and coupled to the mechanical resonator to control the mechanical resonator.

10. The device of claim 9, wherein the integrated circuitry actuates the mechanical resonator and/or detects vibration of the mechanical resonator.

11. The device of claim 8, wherein the device further comprises integrated circuitry formed on the cap and coupled to the mechanical resonator to control the mechanical resonator.

12. The device of claim 11, wherein the integrated circuitry actuates the mechanical resonator and/or detects vibration of the mechanical resonator.

13. The device of claim 1, further comprising a stack of a plurality of layers of alternating low and high acoustic impedance integrated with the substrate.

14. The device of claim 13, wherein the mechanical resonator is a solidly mounted mechanical resonator integrated with the stack.

15. The device of claim 1, wherein the mechanical resonator has an operating frequency ranging from 30 to 35 kHz.

16. The device of claim 1, wherein the mechanical resonator has an operating frequency ranging from 60 to 70 kHz.

17. The device of claim 1, wherein the mechanical resonator has an operating frequency ranging from 10 Mhz to 1 GHz.

18. The device of claim 1, wherein the mechanical resonator has an operating frequency ranging from 1 GHz to 3 GHz.

19. The device of claim 1, wherein the mechanical resonator has an operating frequency ranging from 3 GHz to 10 GHz.

20. A device comprising:

a substrate comprising a first material; and

a mechanical resonator comprising quartz and integrated with the substrate,

wherein the first material is not quartz.

21. The device of claim 20, wherein the mechanical resonator comprises single crystal quartz.

22. The device of claim 21, wherein the first material is single crystal silicon.

23. The device of claim 20, further comprising a cap bonded to the substrate to form a hermetically sealed environment for the mechanical resonator.

24. The device of claim 23, further comprising integrated circuitry formed on the substrate and coupled to the mechanical resonator to control the mechanical resonator.

26. The device of claim 20, wherein the mechanical resonator has a resonance frequency between approximately 50 MHz and 1 GHz.

27. The device of claim 20, wherein the mechanical resonator has a resonance frequency between approximately 30 kHz and 35 kHz.

28. The device of claim 20, wherein the mechanical resonator has a resonance frequency between approximately 3 GHz and 10 GHz.

25. The device of 23, further comprising integrated circuitry formed on the cap and coupled to the mechanical resonator to control the mechanical resonator

29. A device comprising:

a substrate comprising a first material;

a mechanical resonator comprising a single crystal piezoelectric material, different from the first material, and integrated with the substrate; and

integrated circuitry coupled to the mechanical resonator.

30. The device of claim 29, wherein the integrated circuitry is formed on the substrate.

31. The device of claim 30, wherein the integrated circuitry controls operation of the mechanical resonator.

32. The device of claim 30, wherein the integrated circuitry detects vibration of the mechanical resonator.

33. The device of claim 30, wherein the substrate is a silicon substrate and wherein the single crystal piezoelectric material comprises quartz.

34. The device of claim 30, wherein the substrate is a silicon substrate and wherein the single crystal piezoelectric material comprises LiTaO₃.

35. A device comprising:

a substrate formed of a semiconductor material comprising silicon;

a mechanical resonator comprising quartz and integrated with the substrate; and

integrated circuitry formed on the substrate and coupled to the mechanical resonator to control operation of the mechanical resonator and/or to detect vibration of the mechanical resonator.

36. The device of claim 35, wherein the quartz is single crystal quartz.

37. The device of claim 35, wherein the integrated circuitry both controls operation of the mechanical resonator and detects vibration of the mechanical resonator.

38. The device of claim 35, wherein the substrate has a cavity formed therein, and wherein the mechanical resonator is suspended above the cavity.

39. The device of claim 35, wherein the mechanical resonator is a quartz resonator.

40. The device of claim 35, wherein the mechanical resonator is a plate acoustic wave resonator.

41. A method of fabricating a device, the method comprising:

bonding a wafer comprising a piezoelectric material to a wafer comprising a first material, the first material being different than the piezoelectric material; and

forming a mechanical resonator from the wafer of the piezoelectric material.

42. The method of claim 41, wherein the piezoelectric material is a single crystal piezoelectric material.

43. The method of claim 42, wherein the piezoelectric material is single crystal quartz.

44. The method of claim 43, wherein the first material comprises silicon.

45. The method of claim 44, wherein the first material comprises single crystal silicon.

46. The method of claim 41, further comprising forming a cavity in the wafer of the first material prior to bonding the wafer comprising the single crystal piezoelectric material to the wafer comprising the first material.

47. The method of claim 42, wherein forming the mechanical resonator comprises forming the mechanical resonator to be suspended above the cavity.