Micro-electro mechanical tunneling switch

• US 8,432,239 B2
• Filed: 11/20/2007
• Issued: 04/30/2013
• Est. Priority Date: 11/20/2006
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bozler, Carl O., Keast, Craig L., Muldavin, Jeremy
• Primary Examiner(s): Rojas, Bernard
• Application Number:
  US11/943,146
• Publication Number:
  US 20080135386A1
• Time in Patent Office: 1,988 Days
• Field of Search: 335/78, 200/181
• US Class Current: 335/78
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: H01H 2059/0063 with stepped actuation, e.g. actuation voltages applied to different sets of electrodes at different times or different spring constants during actuation
• CPC Class Codes: H01H 2059/0072 with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

A micro-electromechanical system switch includes a substrate and a plurality of actuating electrodes formed the substrate wherein each actuating electrode is activatable. A cantilever beam has a first end and a second end and a plurality of stops formed thereon. The plurality of stops engages the substrate between the plurality of actuating electrode. A contact area is formed in the substrate and located to engage the second end of the cantilever beam. A voltage source applies a voltage to each actuating electrode independently in a sequence from an actuating electrode located adjacent to the first end of the cantilever beam to an actuating electrode located adjacent to the second end of the cantilever beam so that the plurality of stops sequentially engage the substrate between the plurality of actuating electrodes.

Claims

1. A micro-electromechanical system switch, comprising:

a substrate;

a plurality of actuating electrodes formed in said substrate, each actuating electrode being activatable;

a cantilever beam having a first end and a second end, said first end of said cantilever beam being anchored to said substrate, said second end of said cantilever beam not being anchored to said substrate;

a plurality of stops formed on said cantilever beam to engage said substrate between said plurality of actuating electrodes, said plurality of stops being a plurality of solid raised areas; and

a contact area formed in said substrate and located to engage said second end of said cantilever beam to form an electrical switch;

one of said plurality of stops being formed on said cantilever beam so as to provide contact to said contact area;

said contact area having a metal contact surface, the metal contact surface having a smoothness of less than 1 nm rms;

said cantilever beam being constructed of a first layer of titanium formed upon a second layer of tungsten, which is formed upon a third layer of titanium.

2. The micro-electromechanical system switch as claimed in claim 1, further comprising a voltage source to apply a voltage to each actuating electrode independently in a sequence from an actuating electrode located adjacent to said first end of said cantilever beam to an actuating electrode located adjacent to said second end of said cantilever beam so that said plurality of stops sequentially engage said substrate between said plurality of actuating electrodes.

3. The micro-electromechanical system switch as claimed in claim 2, wherein a gap is formed between a second end of said cantilever beam and said contact area when all actuating electrodes, but the actuating electrode located adjacent to said second end of said cantilever beam, have been actuated.

4. The micro-electromechanical system switch as claimed in claim 3, wherein said gap is less than 100 nm.

5. The micro-electromechanical system switch as claimed in claim 3, wherein said gap is 1 to 30 nm.

6. The micro-electromechanical system switch as claimed in claim 2, wherein an effective gap is formed between a second end of said cantilever beam and said contact area when all actuating electrodes have been actuated.

7. The micro-electromechanical system switch as claimed in claim 6, wherein said effective gap is less than 1 nm.

8. The micro-electromechanical system switch as claimed in claim 6, wherein said effective gap substantially prevents metal atoms in said second end of said cantilever from physically contacting metal atoms in said contact area.

9. The micro-electromechanical system switch as claimed in claim 1, further comprising a voltage source to apply a voltage to each actuating electrode independently in a sequence from an actuating electrode located adjacent to said first end of said cantilever beam to an actuating electrode located adjacent to said second end of said cantilever beam so that the micro-electromechanical system switch closes in stages.

10. The micro-electromechanical system switch as claimed in claim 1, wherein said plurality of stops is constructed of platinum.

11. The micro-electromechanical system switch as claimed in claim 1, wherein said contact area includes an anti-stick layer formed thereon.

12. The micro-electromechanical system switch as claimed in claim 11, wherein said anti-stick layer is constructed of a silicon dioxide monolayer.

13. The micro-electromechanical system switch as claimed in claim 11, wherein said anti-stick layer is constructed of a monolayer layer of carbon.

14. The micro-electromechanical system switch as claimed in claim 11, wherein said anti-stick layer is constructed of a monolayer layer of oxygen.

15. The micro-electromechanical system switch as claimed in claim 1, wherein said cantilever beam includes strain relieving slits.

16. The micro-electromechanical system switch as claimed in claim 1, wherein said first end of said cantilever beam is thinner than said second end of said cantilever beam.

17. The micro-electromechanical system switch as claimed in claim 1, wherein a thickness of said cantilever beam increase from said first end of said cantilever beam to said second end of said cantilever beam.

18. The micro-electromechanical system switch as claimed in claim 1, further comprising an anti-stick layer formed on said contact area.

19. The switch as claimed in claim 18, wherein said anti-stick layer is constructed of a silicon dioxide monolayer.

20. The switch as claimed in claim 18, wherein said anti-stick layer is constructed of a monolayer layer of carbon.

21. The switch as claimed in claim 18, wherein said anti-stick layer is constructed of a monolayer layer of oxygen.

22. The switch as claimed in claim 18, wherein an effective gap of less than 1 nm is formed by said anti-stick layer.

23. The switch as claimed in claim 18, wherein an effective gap is formed by said anti-stick layer;

said effective gap substantially preventing metal atoms in said contact area from physically contacting metal atoms in said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area.

24. The micro-electromechanical system switch as claimed in claim 1, wherein said contact area and said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area having an effective gap there between when said contact area and said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area provide a closed switch.

25. The switch as claimed in claim 24, wherein the effective gap is an anti-stick layer formed on said contact area.

26. The switch as claimed in claim 24, wherein the effective gap is an anti-stick layer formed on said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area.

27. The switch as claimed in claim 24, wherein the effective gap substantially prevents metal atoms in said contact area and said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area from actual physical contact.

28. The switch as claimed in claim 24, wherein the effective gap is realized by said contact area and said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area are non-atomically smooth.

29. The switch as claimed in claim 24, wherein said contact area and said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area having a gap there between which is less than 50 nm when said contact area and said one of said plurality of stops being formed on said cantilever beam providing contact to said contact area provide an open switch.

30. A micro-electromechanical system switch, comprising:

a substrate;

a plurality of actuating electrodes formed in said substrate, each actuating electrode being activatable;

a cantilever beam having a first end and a second end;

a plurality of stops formed on said substrate to engage said cantilever beam between said plurality of actuating electrodes; and

a metal contact area formed in said substrate and located to engage said second end of said cantilever beam to form an electrical switch;

said metal contact area having a metal contact surface, the metal contact surface having a smoothness of less than 1 nm rms;

said cantilever beam being constructed of a first layer of titanium formed upon a second layer of tungsten, which is formed upon a third layer of titanium.

31. The micro-electromechanical system switch as claimed in claim 30, further comprising a voltage source to apply a voltage to each actuating electrode independently in a sequence from an actuating electrode located adjacent to said first end of said cantilever beam to an actuating electrode located adjacent to said second end of said cantilever beam so that said plurality of stops sequentially engage said substrate between said plurality of actuating electrodes.

32. The micro-electromechanical system switch as claimed in claim 31, wherein a gap is formed between a second end of said cantilever beam and said metal contact area when all actuating electrodes, but the actuating electrode located adjacent to said second end of said cantilever beam, have been actuated.

33. The micro-electromechanical system switch as claimed in claim 32, wherein said gap is less than 100 nm.

34. The micro-electromechanical system switch as claimed in claim 32, wherein said gap is 1 to 30 nm.

35. The micro-electromechanical system switch as claimed in claim 31, wherein an effective gap is formed between a second end of said cantilever beam and said metal contact area when all actuating electrodes have been actuated.

36. The micro-electromechanical system switch as claimed in claim 35, wherein said effective gap is less than 1 nm.

37. The micro-electromechanical system switch as claimed in claim 35, wherein said effective gap substantially prevents metal atoms in said second end of said cantilever from physically contacting metal atoms in said metal contact area.

38. The micro-electromechanical system switch as claimed in claim 30, further comprising a voltage source to apply a voltage to each actuating electrode independently in a sequence from an actuating electrode located adjacent to said first end of said cantilever beam to an actuating electrode located adjacent to said second end of said cantilever beam so that the micro-electromechanical system switch closes in stages.

39. The micro-electromechanical system switch as claimed in claim 30, wherein said plurality of stops is constructed of platinum.

40. The micro-electromechanical system switch as claimed in claim 30, wherein said metal contact area includes an anti-stick layer formed thereon.

41. The micro-electromechanical system switch as claimed in claim 40, wherein said anti-stick layer is constructed of a silicon dioxide monolayer.

42. The micro-electromechanical system switch as claimed in claim 40, wherein said anti-stick layer is constructed of a monolayer layer of carbon.

43. The micro-electromechanical system switch as claimed in claim 40, wherein said anti-stick layer is constructed of a monolayer layer of oxygen.

44. The micro-electromechanical system switch as claimed in claim 30, wherein said cantilever beam includes strain relieving slits.

45. The micro-electromechanical system switch as claimed in claim 30, wherein said first end of said cantilever beam is thinner than said second end of said cantilever beam.

46. The micro-electromechanical system switch as claimed in claim 30, wherein a thickness of said cantilever beam increase from said first end of said cantilever beam to said second end of said cantilever beam.

47. A micro-electromechanical system switch, comprising:

a substrate;

a plurality of actuating electrodes formed in said substrate, each actuating electrode being activatable;

a cantilever beam having a first end and a second end;

a plurality of stops formed on said substrate to engage said cantilever beam; and

a metal contact area formed in said substrate and located to engage said second end of said cantilever beam;

said metal contact area having a metal contact surface, the metal contact surface having a smoothness of less than 1 nm rms;

said cantilever beam being constructed of a first layer of titanium formed upon a second layer of tungsten, which is formed upon a third layer of titanium.

48. The micro-electromechanical system switch as claimed in claim 47, wherein a gap is formed between a second end of said cantilever beam and said metal contact area, said gap being less than 100 nm.

49. The micro-electromechanical system switch as claimed in claim 47, wherein a gap is formed between a second end of said cantilever beam and said metal contact area, said gap being 1 to 30 nm.

50. The micro-electromechanical system switch as claimed in claim 47, wherein an effective gap is formed between a second end of said cantilever beam and said metal contact area when said actuating electrode has been actuated.

51. The micro-electromechanical system switch as claimed in claim 50, wherein said effective gap is less than 1 nm.

52. The micro-electromechanical system switch as claimed in claim 50, wherein said effective gap substantially prevents metal atoms in said second end of said cantilever from physically contacting metal atoms in said metal contact area.

53. The micro-electromechanical system switch as claimed in claim 47, wherein said plurality of stops is constructed of platinum.

54. A micro-electromechanical system switch, comprising:

a substrate;

an actuating electrode formed in said substrate;

a cantilever beam having a first end and a second end;

a plurality of stops formed on said cantilever beam to engage said substrate; and

a metal contact area formed in said substrate and located to engage said second end of said cantilever beam;

said metal contact area having a contact surface, the metal contact surface having a smoothness of less than 1 nm rms;

said cantilever beam being constructed of a first layer of titanium formed upon a second layer of tungsten, which is formed upon a third layer of titanium.

55. The micro-electromechanical system switch as claimed in claim 54, wherein a gap is formed between a second end of said cantilever beam and said metal contact area, said gap being less than 100 nm.

56. The micro-electromechanical system switch as claimed in claim 54, wherein a gap is formed between a second end of said cantilever beam and said metal contact area, said gap being 1 to 30 nm.

57. The micro-electromechanical system switch as claimed in claim 54, wherein an effective gap is formed between a second end of said cantilever beam and said metal contact area when said actuating electrode has been actuated.

58. The micro-electromechanical system switch as claimed in claim 57, wherein said effective gap is less than 1 nm.

59. The micro-electromechanical system switch as claimed in claim 57, wherein said effective gap substantially prevents metal atoms in said second end of said cantilever from physically contacting metal atoms in said metal contact area.

60. The micro-electromechanical system switch as claimed in claim 54, wherein said plurality of stops is constructed of platinum.