Nano-electromechanical switch

Patent metadata

Field	Value
Publication number	US-9611134-B2
Application number	US-201514697299-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Dec 7, 2011
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A nano-electromechanical switch and a method for designing a nano-electromechanical switch. The nano-electromechanical switch includes at least one actuator electrode and a curved cantilever beam. The curved cantilever beam is adapted to flex in response to an activation voltage applied between the actuator electrode and the curved cantilever beam to provide an electrical contact between the curved cantilever beam and an output electrode of the nano-electromechanical switch. Before, during and after the curved cantilever beam flex in response to the activation voltage, a remaining gap between the curved cantilever beam and the actuator electrode is uniform.

First claim

What is claimed is:

1. A nano-electromechanical switch, comprising:
at least one actuator electrode having a surface with a first curvature extending along at least a majority of a length of the at least one actuator electrode; and
a curved cantilever beam having a main body portion with a second curvature along a majority of its length that substantially matches said first curvature of the at least one actuator electrode, wherein the main body portion of the curved cantilever beam is curved without an application of an activation voltage to provide a uniform gap separating the at least one actuator electrode from the curved cantilever beam prior to actuation, wherein said curved cantilever beam flexes in response to an activation voltage applied between said actuator electrode and said curved cantilever beam to provide an electrical contact between said curved cantilever beam and an output electrode of said nano-electromechanical switch, wherein a flexible hinge portion of said curved cantilever beam connects said curved cantilever beam with an input electrode of said nano-electromechanical switch, wherein said flexible hinge portion is less stiff than said main body portion of said curved cantilever beam so that the motion of the curved cantilever beam approximates a rotation around said flexible hinge portion and forms said point of rotation.

2. The nano-electromechanical switch according to claim 1 , wherein a motion direction angle between a direction of motion of said curved cantilever beam around a point of rotation and a surface of said curved cantilever beam facing said actuator electrode is configured so that after rotation of said curved cantilever beam the remaining gap between said curved cantilever beam and said actuator electrode is constant.

3. The nano-electromechanical switch according to claim 2 , wherein said motion direction angle between a direction of motion of said curved cantilever beam around said point of rotation and a surface of said curved cantilever beam facing said actuation electrode is constant.

4. The nano-electromechanical switch according to claim 2 , wherein said cantilever beam comprises said flexible hinge portion.

5. The nano-electromechanical switch according to claim 2 , wherein said main body portion being mechanically stiffer than said hinge portion and performing a circular motion around said flexible hinge portion in response to said activation voltage applied between said actuation electrode and said curved cantilever beam.

6. The nano-electromechanical switch according to one claim 1 , wherein an initial gap between said curved cantilever beam and said actuator electrode is determined by a thickness of a sacrificial layer used during fabrication of said nano-electromechanical switch.

7. The nano-electromechanical switch according to claim 3 , wherein the motion direction angle between the direction of motion of said curved cantilever beam around said point of rotation and the surface of said curved cantilever beam facing the actuator electrode is along the main body portion of said curved cantilever beam and is equal to 30 degrees.

8. A method for designing a nano-electromechanical switch, comprising:
adapting a curved cantilever beam to rotate around a point of rotation in response to an activation voltage applied between an actuator electrode and said curved cantilever beam, the at least one actuator electrode having a first curvature extending along a length of the at least one actuator electrode, and the curved cantilever beam having a main body portion with a second curvature that substantially matches the first curvature to provide a closed state actuation gap (CSAG) between the at least one actuator and the main body portion that is uniform along its length prior to actuation, wherein said second curvature is present in said main body portion without the application of the activation voltage, wherein a motion direction angle between a direction of motion of said curved cantilever beam around said point of rotation and a surface of said curved cantilever beam facing said actuator electrode is configured so that after rotation of said curved cantilever beam the remaining gap between said curved cantilever beam and said actuator electrode is uniform; and
providing an electrical contact between said curved cantilever beam and an output electrode of said nano-electromechanical switch.

9. The method for designing a nano-electromechanical switch according to claim 8 , wherein the motion direction angle between the direction of motion of said curved cantilever beam around said point of rotation and the surface of said curved cantilever beam facing that actuator electrode is maintained constant.

10. The method for designing a nano-electromechanical switch according to claim 8 , wherein Cartesian coordinates (x, y) of the curved cantilever beam alone the actuator electrode are calculated iteratively starting from an outermost line segment at a tip (x0, y0) of said curved cantilever beam by using the following equations:
wherein αi−1 is a normal angle between a direction normal of the direction of motion of said curved cantilever beam around said point of rotation and the surface of said cantilever beam facing said actuator electrode, and lS is a predetermined line segment length.

11. The method for designing a nano-electromechanical switch according to claim 8 , wherein for achieving a constant remaining gap between said curved cantilever beam and said actuator electrode the normal angle is adapted for each line segment as follows:
wherein the ratio is the ratio of a closed state to an open state gap, R is a maximum radius of the curved cantilever beam at its tip and r is a distance of a surface intersection point of said curved cantilever beam facing said actuator electrode from a point of rotation.

12. The method for designing a nano-electromechanical switch according to claim 9 , wherein the normal angle is kept constant along the actuator electrode.

13. The method for designing a nano-electromechanical switch according to claim 12 , wherein the normal angle is kept at about 60 degrees starting from the tip of said cantilever beam along a main body portion of said cantilever beam until the distance of the surface intersection point of said cantilever beam facing said actuator electrode from the point of rotation becomes about half of the maximum radius of said curved cantilever beam being a distance between the tip of said cantilever beam and the point of rotation.

14. A computer readable non-transitory article of manufacture tangibly embodying computer readable instructions which, when executed, cause a computer to carry out the steps of a method, comprising:
adapting a curved cantilever beam to rotate around a point of rotation in response to an activation voltage applied between an actuator electrode and said curved cantilever beam, the at least one actuator electrode having a first curvature extending along a length of the at least one actuator electrode, and the curved cantilever beam having a main body portion with a second curvature that substantially matches the first curvature to provide a closed state actuation gap (CSAG) between the at least one actuator and the main body portion that is uniform along its length prior to actuation, wherein said second curvature is present in said main body portion without the application of the activation voltage, wherein a motion direction angle between a direction of motion of said curved cantilever beam around said point of rotation and a surface of said curved cantilever beam facing said actuator electrode is configured so that after rotation of said curve

Assignees

• IBM

Inventors

• Despont Michel
• Grogg Daniel
• Knoll Armin W

Classifications

• B81C99/006

  Design; Simulation · CPC title

• G06F30/17

  Mechanical parametric or variational design · CPC title

• B81B2203/0118

  Cantilevers · CPC title

• B81B3/0027 Primary

  Structures for transforming mechanical energy, e.g. potential energy of a spring into translation, sound into translation · CPC title

• H01H1/0094 Primary

  Switches making use of nanoelectromechanical systems [NEMS] · CPC title