Carbon nanotube processing and chemistry for electronic interconnect applications

Carbon nanotubes possess many properties that are ideally suited for electronic applications, such as metallic/semiconducting behavior and ballistic transport. Specifically, in light of mounting concerns over the increasing resistivity of the state-of-the-art interconnect material, copper, and the associated rise in interconnect power consumption and delay, carbon nanotubes are seen as a potential candidate for a future interconnect material. However, current integrated circuit manufacturing processes are ill-equipped to deal with discrete nanomaterials such as carbon nanotubes. In this thesis, several methods for the deposition and directed assembly of as-grown carbon nanotubes are examined. A metal/CNT-film structure is proposed as a relatively simple method to incorporate CNTs into an interconnect structure. Resistance comparisons between structures formed from films of Pd and randomly-aligned SWNTs and control Pd structures are highly variable, indicating that Pd/CNT processing techniques need significant refinement. However, comparisons between structures fabricated with films of randomly-aligned SWNTs and Pd control resistors show that randomly-aligned SWNT films are not competitive with pure metal structures, due to the low packing density and alignment inherent to these films. Finally, a covalent chemical CNT functionalization method to improve CNT handling without degradation in electronic conductivity is examined. SWNTs functionalized with this conductance-preserving carbene-CNT reaction, first reported by Lee et al [1], show resistance about an order of magnitude higher than unfunctionalized SWNTs but also an order of magnitude lower than SWNTs functionalized via a more typical covalent chemistry. In addition, evidence for controllable Fermi level shifting is seen for carbene-functionalized SWNTs, with shifts of up to 100 mV observed, and varying depending on the extent of functionalization and type of carbene group used.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Wu, Tan Mau, 1979-

Advisor dc:contributor.advisor

• Francesco Stellacci.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/44720

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/44720