Bulk resonator

• US 6,936,954 B2
• Filed: 08/28/2002
• Issued: 08/30/2005
• Est. Priority Date: 08/29/2001
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Peczalski, Andrzej
• Primary Examiner(s): Dougherty, Thomas M.
• Assistant Examiner(s): ADDISON, KAREN B
• Application Number:
  US10/231,806
• Publication Number:
  US 20030057806A1
• Time in Patent Office: 1,098 Days
• Field of Search: H01/L04.1/08, H01/L02.4/82, 310/346, 310/324, 310/328, 310/339, 310/338, 310/311, 310/320, 310/330, 310/332, 310/357
• US Class Current: 310/346
• CPC Class Codes: H03H 3/04 for obtaining desired frequency or temperature coefficient

Abstract

A resonator having temperature and electronic compensation. The resonator has several layers on a substrate having opposite thermal coefficients of the sound velocity for temperature compensation. Also, the frequency of the resonator is adjusted in accordance with an external time reference. The resonator has a high quality factor and a very small size.

Claims

1. A resonator comprising:

a first layer of dielectric;

a second layer of silicon formed on said first layer of dielectric;

a third layer of a piezoelectric material formed on a first portion of said second layer;

a fourth layer of amorphous material formed on said third layer or the bottom of said first layer of dielectric;

a fifth layer formed on a second portion of said second layer;

a first contact layer formed on said fourth and fifth layers; and

a second contact formed on a third portion of said second layer.

2. The resonator of claim 1, further comprising:

a frequency counter connected to said first and second contacts;

a heater thermally proximate to said resonator;

a reference time source; and

a compare count and adjust heater device, connected to said frequency counter, said heater and to said reference time source.

3. The resonator of claim 2, wherein:

said first layer is SiO₂;

said third layer is of a piezoelectric group including GaN, AlN and AlGaN;

said fourth layer is of amorphous material group including SiO₂, silicon nitride and amorphous silicon;

said fifth layer is SiO₂;

said first contact layer is an electrically conducting material; and

said second contact layer is electrically conducting material.

4. The resonator of claim 3, wherein said third and fourth layers have opposite thermal coefficients of sound velocity.

5. The resonator of claim 4, wherein said compare count and adjust heater device compares a resonator frequency count indication from said frequency counter with said reference time source and sends a signal to said heater that heats or not heats said resonator to change a frequency of said resonator so as to adjust the frequency to match a corresponding value of said frequency counter output to said time reference source.

6. The resonator of claim 4, wherein:

said reference time source provides a signal periodically after a given period of time;

said frequency counter periodically provides a count of oscillations of said resonator during the given period of time; and

said compare count and adjust heater device compares the count with a predetermined count and sends a signal to said heater which in turn adjusts the count of oscillations of said resonator.

7. A resonator comprising:

a first layer of dielectric material;

a second layer of the first material on said first layer;

a third layer of piezoelectric material on said second layer; and

a fourth layer of amorphous material on said third layer.

8. The resonator of claim 7, wherein said third layer is on a first portion of said second layer.

9. The resonator of claim 8, further comprising a fifth layer of dielectric on a second portion of said second layer.

10. The resonator of claim 9 further comprising a first contact layer on at least a portion of said fifth layer and said fourth layer.

11. The resonator of claim 10, further comprising a second contact layer on at least a portion of said second layer.

12. The resonator of claim 9 wherein said fourth layer is on said fifth layer.

13. The resonator of claim 12 further comprising a contact on said second layer.

14. The resonator of claim 13, wherein said fourth layer is a contact.

15. The resonator of claim 9, further comprising:

a heater proximate to said resonator;

a frequency sensor proximate to said resonator;

a frequency counter connected to said frequency sensor; and

a control device connected to said frequency counter and to said heater.

16. The resonator of claim 15, wherein said control device is connected to a time reference.

17. The resonator of claim 16, wherein:

a first count of a predetermined frequency, during a given period of the time reference, may be compared by said control device with a second count of a frequency of said resonator from said frequency counter; and

said control device may change the frequency of said resonator by changing the temperature of said resonator via said heater, so that the first and second counts are approximately equal.

18. The resonator of claim 17, wherein said heater is part of said resonator.

19. The resonator of claim 18, wherein said resonator may be heated by applying a current to said resonator.

20. The resonator of claim 9, further comprising:

a frequency counter connected to said resonator; and

a control device connected to said frequency counter, to said resonator, and to a time reference.

21. The resonator of claim 20, wherein:

a first count of a predetermined frequency, during a given period of the time reference, may be compared by said control device with a second count from said frequency counter of a frequency of said resonator; and

said control device may change the frequency of said resonator so that the first and second counts are approximately equal.

22. The resonator of claim 21, wherein said control device may change the frequency of said resonator by applying a current to said resonator.

44. The resonator of claim 14, further comprising a sixth layer on the bottom of a portion of said first layer.

23. A resonator comprising:

means for resonating;

means for attaining a first count of a frequency of said means for resonating during a time reference period;

means for attaining a second count of a predetermining frequency during the time reference period; and

means for changing the frequency of said means for resonating so that the first count is approximately equal to the second count.

24. The resonator of claim 23, wherein said means for changing the frequency of said means for resonating comprises a means for affecting a temperature of said means for resonating.

25. The resonator of claim 24, wherein said means for resonating comprises:

a support structure;

a first layer, having dielectric material, on said support structure;

a second layer, having a first material, on said first layer;

a third layer, having piezoelectric material, on at least a portion of said second layer; and

a fourth layer, having an amorphous material, on said third layer.

26. The resonator of claim 25, wherein said means for resonating further comprises a fifth layer, having conductive material, between said second and third layers.

27. The resonator of claim 26, wherein said means for resonating further comprises a sixth layer, having dielectric material, on at least a portion of said second layer.

28. The resonator of claim 27, wherein said means for resonating further comprises a first contact layer on at least a portion of said sixth layer and said fourth layer.

29. The resonator of claim 28, wherein said means for resonating further comprises a second contact layer on at least a portion of said second layer.

30. The resonator of claim 27, wherein said fourth layer is on said sixth layer.

31. The resonator of claim 30, wherein said means for resonating comprises a contact on said second layer.

32. The resonator of claim 31, wherein said fourth layer is a contact.

33. The resonator of claim 32, wherein the first material is silicon.

34. The resonator of claim 29, wherein the first material is silicon.

35. A resonator comprising:

a support structure;

a first layer, having dielectric material, on said support structure;

a second layer, having a first material, on said first layer;

a third layer, having conductive material, on a portion of said second layer;

a fourth layer, having piezoelectric material, on a second portion of said second layer; and

a fifth layer, having amorphous material, on said fourth layer.

36. The resonator of claim 35, further comprising a sixth layer, having dielectric material, on a portion of said second layer.

37. The resonator of claim 36, further comprising:

a seventh layer, having contact material, on said fifth and sixth layers; and

an eighth layer, having contact material, on a portion of said second layer.

38. The resonator of claim 36, wherein said fifth layer has contact material.

39. The resonator of claim 38, further comprising a seventh layer, having contact material on a portion of said second layer.

40. The resonator of claim 37, further comprising a frequency stabilizer.

41. The resonator of claim 40, wherein said frequency stabilizer comprises:

a frequency counter connected to an output of said resonator; and

a compare count connected to an output of said frequency counter, an output of a time reference, and to an input of said resonator.

42. The resonator of claim 39, further comprising a frequency stabilizer.

43. The resonator of claim 42, wherein said frequency stabilizer comprises:

a frequency counter connected to an output of said resonator; and

a compare count connected to an output of said frequency counter, an output of a time reference, and an input of said resonator.