Microelectromechanical resonator

Patent metadata

Field	Value
Publication number	US-10218333-B2
Application number	US-201715497146-A
Country	US
Kind code	B2
Filing date	Apr 25, 2017
Priority date	Feb 9, 2014
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A moveable micromachined member of a microelectromechanical system (MEMS) device includes an insulating layer disposed between first and second electrically conductive layers. First and second mechanical structures secure the moveable micromachined member to a substrate of the MEMS device and include respective first and second electrical interconnect layers coupled in series, with the first electrically conductive layer of the moveable micromachined member and each other, between first and second electrical terminals to enable conduction of a first joule-heating current from the first electrical terminal to the second electrical terminal through the first electrically conductive layer of the moveable micromachined member.

First claim

What is claimed is:

1. A microelectromechanical system (MEMS) device comprising:
a moveable micromachined member having a piezoelectric insulating layer disposed between first and second electrically conductive layers;
a substrate;
first and second electrical terminals; and
first and second mechanical structures that secure the moveable micromachined member to the substrate and include respective first and second electrical interconnect layers coupled in series, with the first electrically conductive layer of the moveable micromachined member and each other, between the first and second electrical terminals to enable conduction of a first joule-heating current from the first electrical terminal to the second electrical terminal through the first electrically conductive layer of the moveable micromachined member.

2. The MEMS device of claim 1 wherein the first electrically conductive layer of the moveable micromachined member is patterned to form first and second regions of relatively low resistance and a relatively high-resistance passageway coupled between the first and second regions.

3. The MEMS device of claim 2 wherein the first and second electrical interconnect layers are electrically coupled to the first and second regions of the first electrically conductive layer such that the relatively high-resistance passageway is coupled in series with the first and second electrical interconnect layers between the first and second electrical terminals.

4. The MEMS device of claim 3 wherein the relatively high-resistance passageway is sized to enable sufficient current flow and energy dissipation to heat the moveable micromachined member to a temperature of at least 300 degrees Celsius.

5. The MEMS device of claim 1 wherein the first and second electrical interconnect layers and the first electrically conductive layer are sized to convey a joule-heating current sufficient to heat the moveable micromachined member to a temperature of at least 300 degrees Celsius.

6. The MEMS device of claim 1 wherein at least one of the first and second electrically conductive layers is a single-crystal silicon layer sufficiently doped to enable electrical conductivity.

7. The MEMS device of claim 1 wherein the piezoelectric insulating layer comprises aluminum nitride.

8. The MEMS device of claim 1 wherein the first and second mechanical structures include respective third and fourth electrical interconnect layers coupled in series, with the second electrically conductive layer of the moveable micromachined member and each other, between the first and second electrical terminals.

9. The MEMS device of claim 1 further comprising an encapsulating structure that forms a vacuum cavity in which the moveable micromachined member and at least portions of the first and second mechanical structures are disposed.

10. The MEMS device of claim 1 wherein the moveable micromachined member comprises a MEMS resonator.

11. The MEMS device of claim 1 wherein the first electrically conductive layer comprises polysilicon sufficiently doped to enable electrical conductivity.

12. The MEMS device of claim 1 wherein the first and second electrical interconnect layers are integral with the first electrically conductive layer of the moveable micromachined member.

13. A microelectromechanical system (MEMS) device comprising:
a moveable micromachined member having an insulating layer disposed between first and second electrically conductive layers:
a substrate;
first and second electrical terminals; and
first and second mechanical structures that secure the moveable micromachined member to the substrate and include respective first and second electrical interconnect layers coupled in series, with the first electrically conductive layer of the moveable micromachined member and each other, between the first and second electrical terminals to enable conduction of a first joule-heating current from the first electrical terminal to the second electrical terminal through the first electrically conductive layer of the moveable micromachined member;
wherein at least one of the first and second electrically conductive layers is a single-crystal silicon layer sufficiently doped to enable electrical conductivity.

14. The MEMS device of claim 13 wherein (i) the first electrically conductive layer of the moveable micromachined member is patterned to form first and second regions of relatively low resistance and a relatively high-resistance passageway coupled between the first and second regions, and (ii) the first and second electrical interconnect layers are electrically coupled to the first and second regions of the first electrically conductive layer such that the relatively high-resistance passageway is coupled in series with the first and second electrical interconnect layers between the first and second electrical terminals.

15. The MEMS device of claim 13 wherein the insulating layer is implemented by a piezoelectric material.

16. The MEMS device of claim 13 wherein the insulating layer comprises aluminum nitride.

17. The MEMS device of claim 13 wherein the first and second electrical interconnect layers are integral with the first electrically conductive layer of the moveable micromachined member.

18. The MEMS device of claim 13 further comprising an encapsulating structure that forms a vacuum cavity in which the moveable micromachined member and at least portions of the first and second mechanical structures are disposed.

19. The MEMS device of claim 13 wherein the moveable micromachined member comprises a MEMS resonator.

20. The MEMS device of claim 13 wherein one of the first and second electrically conductive layers comprises polysilicon sufficiently doped to enable electrical conductivity.

Assignees

• SiTime Coporation
• Sitime Corp

Inventors

• Doll Joseph C
• Miller Nicholas
• Grosjean Charles I
• Hagelin Paul M
• Hill Ginel C

Classifications

• H03H9/1057

  for microelectro-mechanical devices · CPC title

• H03H9/02259

  Driving or detection means · CPC title

• H03H9/02401

  by annealing · CPC title

• H03H2009/155

  using MEMS techniques · CPC title

• H03H9/125 Primary

  Driving means, e.g. electrodes, coils · CPC title