Novel fabrication technologies of planar nano-gap electrodes for single molecule evaluation

Present information technologies use semiconductor devices and magnetic/optical disc. However, they are all foreseen to face fundamental limitations within a decade. Therefore, superseding devices are required for the next paradigm of high performance information technologies. This paper describes prospects for single molecule devices suitable for future information processing technologies, which are expected as the most probable candidate to supersede the present semiconductor devices. The first milestone towards the realization of single molecule devices in future electronics requires quantitative evaluation of single molecule characteristics, which inevitably needs planar nano-gap electrodes between which single molecules are sandwiched, observed their structures and measured their electrical characteristics. Nano-meter electrode pattern fabrication was achieved by electron beam lithography and metal lift-off, while planarization process requires many new technologies including chemical–mechanical polishing (CMP) and wafer bonding. The detailed planarization processing technologies are described in this paper to realize nm-planar nano-scale electrodes.