Micromechanical switching devices

• US 6,153,839 A
• Filed: 10/22/1998
• Issued: 11/28/2000
• Est. Priority Date: 10/22/1998
• Status: Expired due to Term

• Current Assignee: Northeastern University
• Original Assignee: Northeastern University
• Inventors: McGruer, Nicol E., Zavracky, Paul M.
• Primary Examiner(s): FRIEDHOFER, MICHAEL A
• Application Number:
  US09/177,229
• Time in Patent Office: 768 Days
• Field of Search: 73/514.16, 73/514.36, 73/514.37, 148/402, 148/563, 200/181, 200/259, 200/16 B, 200/16 D, 200/512, 200/61.48, 200/262-270, 251/275, 257/418, 257/419, 257/773, 257/784, 257/580, 310/309, 310/328, 330/278, 330/295, 330/307, 333/262, 334/55, 337/139, 337/140, 359/230, 361/233, 361/234, 385/16, 385/20
• US Class Current: 200/181
• CPC Class Codes: H01H 1/20 Bridging contacts for circuit breakers H01H73/045
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01H 9/40 Multiple main contacts for the purpose of dividing the current through, or potential drop along, the arc

Abstract

A micromechanical switch or relay in accordance with the invention includes a substrate, a source electrode, a gate electrode, a drain electrode, and various style beams. In one embodiment the beam is relatively long and includes flexures on at least one end, and has a small activation voltage. Additional embodiments include a relay wherein the beam has an insulator and an isolated contactor wherein the interface between the beam and the insulator is more mechanically robust by having the insulator fill recesses in the end of the beam; a switch or relay wherein the drain contacts are collinear with the source contacts so that the strain gradient of the mechanical material does not affect performance of the device; a snap action switch in which the beam acts a leaf spring such that an initial voltage places the beam close to the contact, and a small additional voltage results in a large beam force for closing the switch contact; a switch or relay wherein the beam includes a hinge and is therefore more easily deflectable; and a single pole double throw switch or relay wherein the beam is deflectable in a first direction to provide a first connection and also deflectable in a second direction to provide a second connection. The switches and relays can be ganged together in order to switch high currents, and can be fabricated to have a single large beam, a single large gate contact, a single large source contact, a single large drain contact, or combinations thereof. Additionally, the switches and relays can be used to form logic circuits such as NAND gates, NOR gates, inverters and the like.

Claims

1. A micromechanical switch comprising:

a substrate;

a source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a drain electrode mounted on said substrate; and

a beam comprising;

a conductive beam body having a first end and a second end, said first end of said beam body including a pair of flexures attached to said source electrode, said beam body overhanging said gate electrode, wherein said pair of flexures adjusts one physical characteristic of said conducting beam; and

said second end of said beam body overhanging said drain electrode, and wherein said second end of said beam body is deflectable from a first position overhanging said drain electrode when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said second end of said beam body is in mechanical and electrical contact with said drain electrode when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

2. The micromechanical device of claim 1, wherein said beam has a length greater than approximately 10 μ

m.

3. The micromechanical device of claim 1, wherein said beam has a length of approximately 70 μ

m.

4. The micromechanical device of claim 1, wherein said micromechanical device is incorporated into a logic circuit.

5. The micromechanical device of claim 1, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

6. The micromechanical device of claim 1, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

7. A micromechanical relay comprising:

a substrate;

a source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a pair of drain contacts mounted on said substrate; and

a beam comprising;

a conductive beam body having a first end, a second end, and an insulator disposed between said first end and said second end, said first end of said beam body including a pair of flexures attached to said source electrode, wherein said pair of flexures adjusts one physical characteristic of said conducting beam, said beam body overhanging said gate electrode, said second end of said beam body overhanging said drain contacts and wherein said second end of said beam body is deflectable from a first position overhanging said drain contacts when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said second end of said beam body is in mechanical and electrical contact with said drain contacts when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

8. The micromechanical device of claim 7, wherein said beam has a length greater than approximately 10 μ

m.

9. The micromechanical device of claim 7, wherein said beam has a length of approximately 70 μ

m.

10. The micromechanical device of claim 7, wherein said micromechanical device is incorporated into a logic circuit.

11. The micromechanical device of claim 7, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

12. The micromechanical device of claim 7, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

13. A micromechanical relay comprising:

a substrate;

a source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a pair of drain contacts mounted on said substrate; and

a beam comprising;

a conductive beam body having a first end, a second end, and an insulator disposed between said first end and said second end, said beam body including at least one recess and said insulator filling said recess for providing a secure mechanical connection of said insulator to said beam body, said first end of said beam body attached to said source electrode, said beam body overhanging said gate electrode, said second end of said beam body overhanging said drain contacts and wherein said second end of said beam body is deflectable from a first position overhanging said drain contacts when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said second end of said beam body is in mechanical and electrical contact with said drain contacts when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

14. The micromechanical device of claim 13, wherein said beam has a length greater than approximately 10 μ

m.

15. The micromechanical device of claim 13, wherein said beam has a length of approximately 70 μ

m.

16. The micromechanical device of claim 13, wherein said micromechanical device is incorporated into a logic circuit.

17. The micromechanical device of claim 13, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

18. The micromechanical device of claim 13, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

19. A micromechanical switch comprising:

a substrate;

a source electrode mounted on said substrate;

a first gate contact and a second gate contact mounted on said substrate;

a drain electrode mounted on said substrate; and

a beam comprising;

a conductive beam body having a first end, a first section, a center portion, a second section, and a second end, said first end of said beam body attached to said source electrode, said first section overhanging said first gate contact, said center portion overhanging said drain electrode, said second end overhanging and extending beyond said second gate contact; and

wherein said beam body is deflectable from a first position overhanging said drain electrode when an electrostatic field of a first intensity is established between said beam body and said first and second gate contacts, to a second position in which said center portion of said beam body is in mechanical and electrical contact with said drain electrode when an electrostatic field of a second intensity is established between said beam body and said first and second gate contacts.

20. The micromechanical device of claim 19, wherein said beam has a length greater than approximately 10 μ

m.

21. The micromechanical device of claim 19, wherein said beam has a length of approximately 70 μ

m.

22. The micromechanical device of claim 19, wherein said micromechanical device is incorporated into a logic circuit.

23. The micromechanical device of claim 19, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

24. The micromechanical device of claim 19, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

25. A micromechanical switch comprising:

a substrate;

a first source electrode and a second source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a drain electrode mounted on said substrate, said first and second source electrodes disposed at opposite ends of said drain electrode so as to be collinear with said drain electrode; and

a beam comprising;

a conductive beam body having a first end, a beam plate, and a second end, said first end of said beam body attached to said first source electrode through a first rectangular support section extending from said first end of said beam body along a first side of said gate electrode to said first source electrode and attached to said second source electrode through a second rectangular support section extending from said first end of said beam body along an opposite side of said gate electrode to said second source electrode, said beam plate overhanging said gate electrode, said second end having a contact area overhanging said drain electrode; and

wherein said beam body is deflectable from a first position overhanging said drain electrode when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said contact area of second end of said beam body is in mechanical and electrical contact with said drain electrode when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

26. The micromechanical device of claim 25, wherein said beam has a length greater than approximately 10 μ

m.

27. The micromechanical device of claim 25, wherein said beam has a length of approximately 70 μ

m.

28. The micromechanical device of claim 25, wherein said micromechanical device is incorporated into a logic circuit.

29. The micromechanical device of claim 25, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

30. The micromechanical device of claim 25, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

31. A micromechanical relay comprising:

a substrate;

a first source electrode and a second source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a pair of drain contacts mounted on said substrate, said first and second source electrodes disposed at opposite sides of said drain contacts so as to be collinear with said drain contacts; and

a beam comprising;

a conductive beam body having a first end, a beam plate, a second end, and an insulator disposed between said first end and said second end of said beam body, said first end of said beam body attached to said first source electrode through a first rectangular support section extending from said first end of said beam body along a first side of said gate electrode to said first source electrode and attached to said second source electrode through a second rectangular support section extending from said first end of said beam body along an opposite side of said gate electrode to said second source electrode, said beam plate overhanging said gate electrode, said second end having a contact area overhanging said drain contacts; and

wherein said beam body is deflectable from a first position overhanging said drain contacts when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said contact area of second end of said beam body is in mechanical and electrical contact with said drain contacts when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

32. The micromechanical device of claim 31, wherein said beam has a length greater than approximately 10 μ

m.

33. The micromechanical device of claim 31, wherein said beam has a length of approximately 70 μ

m.

34. The micromechanical device of claim 31, wherein said micromechanical device is incorporated into a logic circuit.

35. The micromechanical device of claim 31, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

36. The micromechanical device of claim 31, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

37. A micromechanical switch comprising:

a substrate;

a source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a drain electrode mounted on said substrate; and

a beam comprising;

a conductive beam body having a first end and a second end, said beam body including a hinge disposed between said first end and second end of said beam body, said hinge being thinner and having a smaller cross-sectional area than said first and second ends of said beam body, said first end of said beam body attached to said source electrode, said beam body overhanging said gate electrode, said second end of said beam body overhanging said drain electrode, and wherein said second end of said beam body is deflectable from a first position overhanging said drain electrode when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said second end of said beam body is in mechanical and electrical contact with said drain electrode when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

38. The micromechanical device of claim 37, wherein said beam has a length greater than approximately 10 μ

m.

39. The micromechanical device of claim 37, wherein said beam has a length of approximately 70 μ

m.

40. The micromechanical device of claim 37, wherein said micromechanical device is incorporated into a logic circuit.

41. The micromechanical device of claim 37, wherein said micromechanical device has an actuation voltage of approximately 100 volts.

42. The micromechanical device of claim 37, wherein said micromechanical device is switched at a frequency of approximately 300 kHz or less.

43. A micromechanical switch comprising:

a substrate;

a source electrode mounted on said substrate;

a gate electrode mounted on said substrate;

a drain electrode mounted on said substrate such that said drain electrode and said gate electrode are adjacent; and

a beam comprising;

a conductive beam body having a first end and a second end, the first end connected to said source electrode; and

said second end of said beam body overhanging said drain electrode and said gate electrode, and wherein said second end of said beam body is deflectable from a first position overhanging said drain electrode when an electrostatic field of a first intensity is established between said beam body and said gate electrode, to a second position in which said second end of said beam body is in mechanical and electrical contact with said drain electrode when an electrostatic field of a second intensity is established between said beam body and said gate electrode.

44. The micromechanical switch of claim 43 wherein said first end of said beam body comprises a pair of flexures attached to said source electrode.

45. The micromechanical switch of claim 43 wherein said beam body further comprises a center portion, and further wherein said first end of said beam body comprises a first pair of flexures attached to said source electrode, said center portion of said beam body comprises a second pair of flexures, and said second end of said beam body comprises a bar connecting said second pair of flexures.