Nanofabrication toward sub-10 nm and its application to novel nanodevices

The device feature size in Si ULSIs has been reduced over the years, and so oner or later we will probably enter the so-called nanoelectronics era. Two nanofabrication technologies, electron-beam lithography and atomic-beam ho lography, which are expected to play an important role in the coming era, a re discussed first. In order to get finer patterns with electron-beam litho graphy, improvements in the characteristics of organic resists are cruciall y important. Organic negative resists with a fine resolution have been deve loped, and a high-quality resist line pattern with a width as small as 7 nm has been successfully formed. A new atom manipulation technique called ato mic-beam holography has been proposed for nanofabrication. It enables direc t pattern formation on a substrate by passing laser-cooled atoms through a computer-generated hologram. It is expected to be a technique with a fine r esolution, reaching the atomic scale, and a high throughput. Nano-size devices are developed from two standpoints. One pursues the minia turization limit of MOS transistors: in this context, we discuss the fabric ation of MOS transistors with gate length down to 14 nm and their electrica l characteristics. The other approach is to explore 'breakthrough devices' that utilize quantum effects: single electron devices are one type of such devices. We discuss the operation of an all-metallic single-electron memory cell along with the electrical characteristics of a single-electron transi stor made of aluminium.