Nanotube fuse structure

• US 7,598,127 B2
• Filed: 11/22/2005
• Issued: 10/06/2009
• Est. Priority Date: 05/12/2005
• Status: Active Grant

• Current Assignee: ZEON Corporation
• Original Assignee: Nantero Incorporated
• Inventors: Bertin, Claude L., Rueckes, Thomas, Whitefield, Bruce J., Allman, Derryl D. J.
• Primary Examiner(s): SMITH, MATTHEW S
• Application Number:
  US11/284,503
• Publication Number:
  US 20060258122A1
• Time in Patent Office: 1,414 Days
• Field of Search: 438/130, 438/132, 327/525, 977/742, 365/96
• US Class Current: 438/132
• CPC Class Codes: H01L 23/5256 comprising fuses, i.e. connections having their state changed from conductive to non-conductive
• CPC Class Codes: H01L 23/5258 the change of state resulting from the use of an external beam, e.g. laser beam or ion beam
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs

Abstract

A method of forming a carbon nanotube fuse by depositing a carbon nanotube layer, then depositing a cap layer directly over the carbon nanotube layer. The cap layer is formed of a material that has an insufficient amount of oxygen to significantly oxidize the carbon nanotube layer under operating conditions, and is otherwise sufficiently robust to protect the carbon nanotube layer from oxygen and plasmas. A photoresist layer is formed over the cap layer, and the photoresist layer is patterned to define a desired size of fuse. Both the cap layer and the carbon nanotube layer are completely etched, without removing the photoresist layer, to define the fuse having two ends in the carbon nanotube layer. Just the cap layer is etched, without removing the photoresist layer, so as to reduce the cap layer by a desired amount at the edges of the cap layer under the photoresist layer, without damaging the carbon nanotube layer. The photoresist layer is removed, and electrically conductive contacts are formed on each of the two ends of the fuse.

Claims

1. A method of forming a carbon nanotube fuse, the method comprising the steps of:

depositing a carbon nanotube layer,

depositing a cap layer directly over the carbon nanotube layer, where the cap layer is formed of a material that has an insufficient amount of oxygen to significantly oxidize the carbon nanotube layer under operating conditions, and is otherwise sufficiently robust to protect the carbon nanotube layer from oxygen and plasmas,

forming a photoresist layer over the cap layer, and patterning the photoresist layer to define a desired size of fuse,

etching completely both the cap layer and the carbon nanotube layer without removing the photoresist layer, to define the fuse having two ends in the carbon nanotube layer,

etching just the cap layer, without removing the photoresist layer, so as to reduce the cap layer by a desired amount at the edges of the cap layer under the photoresist layer, without damaging the carbon nanotube layer,

removing the photoresist layer, and

forming electrically conductive contacts on each of the two ends of the fuse.

2. A method of severing an electrically conductive carbon nanotube fuse having a link between two contacts that are disposed on distal ends of the link, the method comprising the step of passing a current between the two contacts and through the link, where the current is sufficient to create a Joule heating effect within the link sufficient to cause at least one of the two contacts to ablate and sever electrical continuity with the end of the link, without the link structurally changing.

3. A carbon nanotube fuse comprising:

a carbon nanotube layer,

a cap layer formed directly over the carbon nanotube layer, where the cap layer is formed of a material that has an insufficient amount of oxygen to significantly oxidize the carbon nanotube layer under operating conditions, and is otherwise sufficiently robust to protect the carbon nanotube layer from oxygen and plasmas, the cap layer formed at a smaller size than the carbon nanotube layer, to expose a contact area at distal ends of the carbon nanotube layer, and

electrically conductive contacts disposed on each of the two distal ends of the carbon nanotube layer and in electrical continuity with the carbon nanotube layer through the contact area,

where the contact area is of a size sufficient for at least one of the contacts to ablate from the carbon nanotube layer upon application of a current that causes a Joule heating effect in the carbon nanotube layer.