Transition metal dielectric alloy materials for MEMS

• US 7,057,246 B2
• Filed: 07/20/2001
• Issued: 06/06/2006
• Est. Priority Date: 08/23/2000
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Reflectivity, Inc. (Texas Instruments, Inc.)
• Inventors: Reid, Jason S.
• Primary Examiner(s): Zarabian, Amir
• Assistant Examiner(s): DUONG, KHANH B
• Application Number:
  US09/910,537
• Publication Number:
  US 20020047172A1
• Time in Patent Office: 1,782 Days
• Field of Search: 438/52, 438/53, 438/455, 438/459, 438/619, 438/951, 257/415, 257/295, 257/296, 257/306, 257/310, 257/417, 257/419, 257/254
• US Class Current: 257/417
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 3/0078 Constitution or structural means for improving mechanical properties not provided for in B81B3/007 - B81B3/0075
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01G 5/40 Structural combinations of variable capacitors with other electric elements not covered by this subclass, the structure mainly consisting of a capacitor, e.g. RC combinations

Abstract

Micromechanical devices are provided that are capable of movement due to a flexible portion. The micromechanical device can have a flexible portion formed of a nitride of preferably an element from groups 3A to 6A of the periodic table (preferably from the first two rows of these groups) and a late transition metal (preferably from groups 8B or 1B of the periodic table). The micromechanical devices can be any device, particularly MEMS sensors or actuators preferably having a flexible portion such as an accelerometer, DC relay or RF switch, optical cross connect or optical switch, or a micromirror part of an array for direct view and projection displays. The flexible portion is preferably formed by sputtering a target having a group 8B or 1B element and a group 3A to 6A element. The target can have other major constituents or impurities (e.g. additional group 3A to 6A element(s)). The target is reactively sputtered in a nitrogen ambient so as to result in a sputtered hinge. It is possible to form both stiff and/or flexible portions of the micromechanical device in this way.

Claims

1. A micromechanical device, comprising:

a movable portion and a flexible portion, the flexible portion comprising a nitride compound and a late transition metal, wherein the nitride compound and late transition metal are in the same film or layer and wherein the film or layer is a ternary or higher system;

wherein the nitride compound is a nitride of silicon, boron or aluminum.

2. The micromechanical device of claim 1, wherein the nitride compound is a silicon nitride or boron nitride.

3. The micromechanical device of claim 1, wherein the late transition metal is selected from the groups 8B or 1B of the periodic table.

4. The micromechanical device of claim 1, wherein the late transition metal is a ferromagnetic metal.

5. The micromechanical device of claim 1, which is a MEMS sensor or actuator.

6. The micromechanical device of claim 1, wherein the late transition metal is a noble metal.

7. The micromechanical device of claim 1, wherein the late transition metal is Co, Ni, Pd, Pt, Ag or Au.

8. The micromechanical device of claim 1, wherein the nitride comprises less than 0.1% oxygen.

9. The micromechanical device of claim 1, wherein the nitride is an oxynitride that comprises up to 10% oxygen.

10. The micromechanical device of claim 1, comprising a substrate, the movable element formed in or on the substrate and a hinge for allowing movement of the movable element relative to the substrate.

11. The micromechanical device of claim 10, wherein the substrate is a semiconductor or light transmissive substrate.

12. The micromechanical device of claim 10, wherein the movable element and/or the hinge are formed of the nitride compound and the late transition metal.

13. The micromechanical device of claim 12, further comprising posts or walls for connecting the movable element to the substrate via the hinge.

14. The micromechanical device of claim 10, wherein the hinge is a sputtered hinge.

15. The micromechanical device of claim 10, wherein the device is a micromirror device with said movable element having a reflective layer thereon or therein.

16. The micromechanical device of claim 15, wherein the reflective layer comprises Al, Ti or Au.

17. The micromechanical device of claim 15, wherein the micromirror device is a light beam steering device.

18. The micromechanical device of claim 17, wherein the light beam steering device is within an optical switch.

19. The micromechanical device of claim 15, wherein the micromirror device is part of a micromirror array in a display.

20. The micromechanical device of claim 19, wherein the display is a direct view or projection display.

21. The micromechanical device of claim 10, which is a sensor.

22. A micromechanical device;

comprising;

a movable portion that is capable of movement due to a flexible portion that comprises a late transition metal and an element from groups 3A to 6A of the periodic table and with the flexible portion being formed by chemical or physical vapor deposition, wherein the late transition metal and the element from groups 3A to 6A of the periodic table are in the same film or layer and wherein the film or layer is a ternary or higher system;

wherein the late transition metal is a noble metal and wherein the flexible portion further comprises more than one element from the first two rows of groups 3A to 6A; and

wherein one of the two or more elements is nitrogen.

23. The micromechanical device of claim 22, wherein the noblemetal of the late transition metal is selected from groups 8B or 1B of the periodic table.

24. The micromechanical device of claim 22, wherein another of the two or more elements is aluminum, boron, silicon carbon or oxygen.

25. The micromechanical device of claim 24, wherein the noble metal of the late transition metal is a ferromagnetic metal.

26. A micromechanical device, comprising:

a flexible hinge comprising a nitride compound and a late transition metal, wherein the nitride compound and late transition metal are in the same film or layer and wherein the film or layer is a ternary or higher system deposited by chemical or physical vapor deposition, wherein the nitride compound is a nitride of silicon, boron or aluminum.

27. The micromechanical device of claim 26, wherein the flexible hinge is attached to a movable portion that is operable to be actuated by an electrostatic force derived from an electrostatic field established between the movable portion and an electrode.

28. A micromechanical device selected from a micromirror, a MEMS switch and a MEMS sensor, comprising:

a movable portion and a flexible hinge to which the movable portion is attached such that the movable portion is operable to move, wherein the flexible hinge comprise a ceramic compound and a late transition metal, wherein the ceramic compound and late transition metal are in the same film or layer and wherein the film or layer is a ternary or higher system deposited by chemical or physical vapor deposition;

wherein the ceramic compound is a nitride compound that is a nitride of silicon, boron or aluminum.

29. The micromechanical device of claim 28, wherein the flexible hinge is attached to a movable portion that is operable to be actuated by an electrostatic force derived from an electrostatic field established between the movable portion and an electrode.

30. A micromechanical device, comprising:

a movable portion and a flexible hinge to which the movable portion is attached such that the movable portion is operable to move, and wherein the flexible hinge comprises a ceramic compound and a late transition metal, wherein the ceramic compound and late transition metal are a ternary or higher system within a common layer, wherein the ceramic compound is a nitride compound which is a nitride of silicon, boron or aluminum.

31. The micromechanical device of claim 30, wherein the flexible hinge is attached to the movable portion that is operable to be actuated by an electrostatic force derived from an electrostatic field established between the movable portion and an electrode.

32. A micromechanical device, comprising:

a flexible portion comprising a nitride compound having an element from groups 3A to 6A of the periodic table and a late transition metal, wherein the nitride compound and late transition metal are in the same film or layer and wherein the film or layer is a ternary or higher system deposited by chemical or physical vapor deposition, wherein the late transition metal is a noble metal.

33. The micromechanical device of claim 32, wherein the flexible portion is a flexible hinge that is operable to be actuated by an electrostatic force derived from an electrostatic field established between the movable portion and an electrode.

34. The micromechanical device of claim 32, wherein the nitride compound is silicon nitride.

35. A micromechanical device, comprising:

a movable portion and a flexible portion, the flexible portion comprising a nitride compound and a late transition metal, wherein the nitride compound and late transition metal are in the same film or layer and wherein the film or layer is a ternary or higher system; and

wherein the late transition metal is noble metal.