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Carbon nanotubes (CNTs) have a large variety of properties that make them attractive for applications in microelectronics. A comparison of carbon nanotube field-effect transistors with silicon MOSFETs shows that CNT devices outperform state-of-the-art silicon transistors. A silicon technology review gives the benchmark for an assessment of the current CNT technology and identifies the growth and placement procedures that are not yet sufficient for industrial applications. Finally, the vertical CNT transistor concept is introduced which deals with the technological problems and opens a new route for 3D integration. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The unique properties of carbon nanotubes (CNTs) make them promising candidates for electrical conductors in microelectronic devices. The parallel integration of CNTs into processes that are compatible with the requirements of the microelectronic industry will be important for their future application in chip devices. We present lithography-based processes to create vertical electrical interconnects made of CNTs. The approach involves catalyst and dielectric (insulator) deposition, lithography, standard etch processes, CVD growth of the CNTs, and the structured deposition of metallic top contacts. This paper will discuss the electrical properties of these CNT vertical interconnects and compare them with the requirements of the ITRS roadmap. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

New results on the planar growth of single-walled carbon nanotubes (SWCNTs) by catalytic chemical vapor deposition (CVD) at low temperatures will be reported. Optimizing catalyst, catalyst support, and growth parameters yields SWCNTs at temperatures as low as 600 °C. Growth at such low temperatures largely affects the diameter distribution since coalescence of the catalyst is suppressed. A phenomenological growth model will be suggested for CVD growth at low temperatures. The model takes into account surface diffusion and is an alternative to the bulk diffusion based vapor-liquid-solid (VLS) model. Furthermore, carbon nanotubes field effect transistors based on substrate grown SWCNTs will be presented. In these devices good contact resistances could be achieved by electroless metal deposition or metal evaporation of the contacts. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We report on the CVD-growth of single-walled carbon nanotubes (SWCNTs) and their electrical characterization. Growth between catalyst covered Mo-pads yields in-situ contacted SWCNTs. With this approach, only one level of conventional photolithography is required to obtain SWCNTs ready for field-effect measurements. The SWCNT yield depends strongly on the catalyst composition and growth conditions, which have been investigated over a wide range. The growth of isolated SWCNTs in lithographically defined holes is also demonstrated. This is the first step towards the realization of surrounding gate vertical SWCNT field-effect transistors (VCNTFET), which are expected to outperform future silicon-based devices. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

An important prerequisite for the implementation of carbon nanotubes (CNTs) in microelectronic circuits is the evaluation of their electronic properties. For this, the generation of low-ohmic electrical contacts between CNTs and metallic circuit lines is crucial. We describe a parallel process which does not rely on e-beam lithography and yields self-aligned, low-ohmic contacts on wafer scale. CNTs that are spray deposited on metallic test structures created by optical lithography are subsequently embedded by electroless metallization and annealed. With this method we are able to simultaneously lower the contact resistance of an unlimited number of CNTs. The reduction of the contact resistance depends on the metals involved and the annealing process. This new method enables the statistical evaluation of the CNT quality dependence on synthesis conditions. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]