AVS 50th International Symposium
    Nanotubes Wednesday Sessions
       Session NT-WeA

Invited Paper NT-WeA7
The Highly Robust Electrical Interconnects and Ultrasensitive Biosensors Based on Embedded Carbon Nanotube Arrays

Wednesday, November 5, 2003, 4:00 pm, Room 317

Session: Properties of Carbon Nanotubes
Presenter: J. Li, NASA Ames Res. Center
Authors: J. Li, NASA Ames Res. Center
A.M. Cassell, NASA Ames Res. Center / Eloret Corp.
J. Koehne, NASA Ames Res. Center
H. Chen, NASA Ames Res. Center / Eloret Corp.
H.T. Ng, NASA Ames Res. Center / Eloret Corp.
Q. Ye, NASA Ames Res. Center / Eloret Corp.
R. Stevens, NASA Ames Res. Center / Eloret Corp.
J. Han, NASA Ames Res. Center / Eloret Corp.
M. Meyyappan, NASA Ames Res. Center
Correspondent: Click to Email
We report on our recent breakthroughs in two different applications using well-aligned carbon nanotube (CNT) arrays on Si chips, including (1) a novel processing solution for highly robust electrical interconnects in integrated circuit manufacturing,@footnote 1@ and (2) the development of ultrasensitive electrochemical DNA sensors.@footnote 2@ Both of them rely on the invention of a bottom-up fabrication scheme which includes six steps, including: (a) lithographic patterning, (b) depositing bottom conducting contacts, (c) depositing metal catalysts, (d) CNT growth by plasma enhanced chemical vapor deposition (PECVD), (e) dielectric gap-filling, and (f) chemical mechanical polishing (CMP). Such processes produce a stable planarized surface with only the open end of CNTs exposed, which can be further processed or modified for different applications. By depositing patterned top contacts, the CNT can serve as vertical interconnects between the two conducting layers. This method is fundamentally different from current damascene processes and avoids problems associated with etching and filling of high aspect ratio holes at nanoscales. In addition, multiwalled CNTs (MWCNTs) are highly robust and can carry a current density of 109 A/cm2 without degradation. It has great potential to help extending the current Si technology. The embedded MWCNT array without the top contact layer can be also used as a nanoelectrode array in electrochemical biosensors. The cell time-constant and sensitivity can be dramatically improved. By functionalizing the tube ends with specific oligonucleotide probes, specific DNA targets can be detected with electrochemical methods down to subattomoles. @FootnoteText@@footnote 1@J. Li, Q. L. Ye Q, A. M. Cassell, H.T. Ng, R. Stevens, J. Han, M. Meyyappan, Appl. Phys. Lett., 82 (15), 2491 (2003). @footnote 2@J. Li, H. T. Ng, A. Cassell, W. Fan, H. Chen, Q. Ye, J. Koehne, J. Han, M. Meyyappan, Nanoletters, in press.