Nanomechanical switches and circuits

• US 6,495,905 B2
• Filed: 06/07/2002
• Issued: 12/17/2002
• Est. Priority Date: 11/09/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Frazier, Gary A., Seabaugh, Alan C.
• Primary Examiner(s): Wilson, Allan R.
• Application Number:
  US10/165,698
• Publication Number:
  US 20020153584A1
• Time in Patent Office: 193 Days
• Field of Search: 257/415, 257/421, 257/423, 257/586, 257/587
• US Class Current: 257/587
• CPC Class Codes: G11C 23/00 Digital stores characterised by movement of mechanical parts to effect storage, e.g. using balls; Storage elements therefor
• CPC Class Codes: H01H 1/0094 Switches making use of nanoelectromechanical systems [NEMS]
• CPC Class Codes: Y10S 977/70 Nanostructure
• CPC Class Codes: Y10S 977/708 with distinct switching device
• CPC Class Codes: Y10S 977/709 including molecular switching device

Abstract

A highly miniaturized nanomechanical transistor switch is fabricated using a mechanical cantilever which creates a conductive path between two electrodes in its deflected state. In one embodiment, the cantilever is deflected by an electrostatic attraction arising from a voltage potential between the cantilever and a control electrode. In another embodiment, the cantilever is formed of a material with high magnetic permeability, and is deflected in response to complementary magnetic fields induced in the cantilever and in an adjacent electrode. The nanomechanical switch can be fabricated using well known semiconductor fabrication techniques, although semiconductor materials are not necessary for fabrication. The switch can rely upon physical contact between the cantilever and the adjacent electrode for current flow, or can rely upon sufficient proximity between the cantilever and the adjacent electrode to allow for tunneling current flow.

Claims

1. A nanomechanical switch comprising:

a substrate;

formed on the substrate, an emitter electrode including a cantilever element extending from the emitter electrode, the emitter being formed of a material having a magnetic permeability greater than one;

a base electrode formed on the substrate, at least a portion of the base electrode being beneath the cantilever element;

a collector electrode formed on the substrate adjacent the base electrode,

at least a portion of the collector electrode being beneath the cantilever element and being formed of a material having a magnetic permeability greater than one; and

a current source coupled to the base electrode.

2. The nanomechanical switch of claim 1 wherein current flowing in the base electrode induces complementary magnetic fields within the cantilever and the collector electrode.

3. The nanomechanical switch of claim 1 wherein the cantilever is spaced apart from the base electrode by less than 40 angstroms when in an undeflected state.

4. The nanomechanical switch of claim 1 wherein the collector electrode is higher, relative the plane of the substrate, than the base electrode.

5. The nanomechanical switch of claim 1 further comprising a lubricating layer formed atop the collector electrode.

6. The nanomechanical switch of claim 1 further comprising interconnection conductors connecting the switch with other circuit elements.

7. The nanomechanical switch of claim 1 wherein a vacuum gap is formed between the cantilever and the collector electrode.

8. The nanomechanical switch of claim 1 wherein a noble gas is placed between the cantilever and the collector electrode.

9. The nanomechanical switch of claim 1 wherein the spacing between the base and collector electrodes is less than 0.07 micrometers.

10. The nanomechanical switch of claim 7 wherein the base collector is formed of a superconducting material.