Nanoprober-Based Pick-and-Place Process for Site-Specific Characterization of Individual Carbon Nanotubes
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1081-P17-04
Nanoprober-Based Pick-and-Place Process for Site-Specific Characterization of Individual Carbon Nanotubes Thomas Hantschel1, Peter Ryan1, Saku Palanne1, Oliver Richard1, Kai Arstila1, Anne S. Verhulst1, Hugo Bender1, Xiaoxing Ke2, and Wilfried Vandervorst1,3 1 AMPS, IMEC, Kapeldreef 75, Leuven, B-3001, Belgium 2 EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp, B-2020, Belgium 3 IKS-Dept Physics, KU Leuven, Celestijnenlaan 200-D, Leuven, B-3001, Belgium ABSTRACT The potential use of carbon nanotubes (CNT) as interconnects requires also new characterization approaches as the existing ones are optimized for three-dimensional materials and do not work for inherently one-dimensional structures like CNTs. Therefore, we have developed a so-called pick-and-place process which allows to remove an individual CNT from a specific site and to place it at another location for further analysis. The approach is based on nanomanipulation combined with scanning electron microscopy (SEM). This paper presents the pick-and-place concept and explains the different steps. We further demonstrate its power by characterizing individual CNTs using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The developed pick-and-place approach overcomes the challenge of sitespecific analysis of CNT interconnects and strongly facilitates the routine analysis of CNTs. INTRODUCTION Carbon nanotubes (CNT) are currently being evaluated as alternative to copper for nanoscale interconnects. Calculations have shown that CNTs can potentially outperform copper in contact holes because of their higher electrical and thermal conductivity as well as their higher maximum current density [1,2]. For this, small diameter CNTs with high density must be grown inside contact holes. The development of such CNT growth and integration processes is challenging and does also require the local characterization of individual CNTs with regard to structure, morphology, electrical properties and defects. Using existing analysis procedures, it is not possible to perform this individual characterization directly after growth or in particular inside the contact hole. A method is therefore desired which allows to transfer individual CNTs from a first to a second sample where the actual analysis will be performed. The commonly used dispersion method which uses ultra-sonic agitation to remove the CNTs from a substrate has shown a number of disadvantages in our experiments: it is not site-specific, it easily causes CNT damage, the involved solvents often remain covering the CNTs, and strong bundling effects are observed for single-wall CNTs (SWCNT). Furthermore, CNTs from different areas of the sample (e.g. contact holes with different diameters) cannot be compared with each other. Therefore, we have developed an approach called pick-and-place which uses a nanomanipulator in combination with scanning electron microscopy (SEM) as sample preparation for individual CNT analysis. We show that pick-and-place is a powerful method to prepare nanos
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