Raman imaging for processing and process monitoring for nanotube devices

We present a process flow for single-walled carbon nanotube electronic and electromechanical device fabrication, where the technique of Raman imaging has been used (i) for the fabrication process monitoring itself and (ii) to consequently observe modifications of the integrated nanotubes during processing. First, extended Raman images (i.e. maps) have been used to locate nanotubes relative to reference alignment markers enabling to distinguish semiconducting from metallic carbon nanotubes before electrically contacting them. Second, we used Raman imaging to monitor individual process steps. We show that the radial breathing mode (RBM) signal is very sensitive to standard processes used to contact individual nanotubes. Moreover, we conclude that HF etching for releasing nanotubes leads to a significant increase of the defect-induced D line. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.