Process integration of carbon nanotubes into microelectromechanical systems

This paper reports on a process flow and characterization for the growth of released carbon nanotubes on polysilicon microelectromechanical devices. We describe a series of post-processing steps to achieve successful integration of CNTs directly into a triple layer polysilicon surface micromachined chip. Individual or multiple tubes can be directly grown between movable posts and electrically connected. The process is characterized to the point where minimum feature sizes and minimum spacing of catalytic seeds are determined as a function of the catalytic solution concentration. We show scanning electron microscopy images and Raman spectroscopy recordings that validate the direct growth of nanotubes. By integrating nanotube growth into batch fabricated microsystems, direct and reliable measurement techniques can be developed and used to accelerate research and identification of nanotube transducer properties. The reported technology is opening the way to the synthesis and evaluation of mechanical nano-scale transducers based on carbon nanotubes. (c) 2006 Elsevier B.V. All rights reserved.