Distinguishing between individual contributions to the via resistance in carbon nanotubes based interconnects

Holger Fiedler, Marius Toader, Sascha Hermann, Raul D. Rodriguez, Evgeniya Sheremet, Michael Rennau, Steffen Schulze, Thomas Waechtler, Michael Hietschold, Dietrich R.T. Zahn, Stefan E. Schulz, Thomas Gessnera

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6 Citations (Scopus)

Abstract

We report on the design and fabrication of carbon nanotube (CNT) vias based on a hybrid metal/CNT technology. The CNTs were integrated on a 4 inch Si wafer platform using conventional semiconductor processes. Multiwalled carbon nanotubes were grown vertically aligned on a copper based metal line. Via holes were prepared using a single damascene process. By employing a substratebased selective deactivation of the catalyst, CNT growth was restricted to the vias. Following this process scheme, the impact of post-CNT growth procedures, like chemical mechanical planarization and sample annealing, were investigated and electrically evaluated using conductive atomic force microscopy and current-voltage (I-V) characterization. Probing 440 individual structures, the resistance of two series-connected 5 ìm vias were determined to be (800 ± 60) Ω after chemical mechanical planarization. By obtaining the I-V characteristics of single CNTs within an individual via, we found that the measured resistance is determined by the contact resistance of the CNT-metal interface. Two mechanisms were found to be relevant here. First partial oxidation of the metal interface during processing, and secondly, stress-induced voiding caused by the high temperatures during the CNT growth process. Changes in the integration scheme to reduce the overall CNT via resistance are proposed.

Original languageEnglish
JournalECS Journal of Solid State Science and Technology
Volume1
Issue number6
DOIs
Publication statusPublished - 1 Dec 2012

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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