Single-Electron Transistors and Circuits for Future Ubiquitous Computing Applications

Single-electron transistors (SETs) are promising as future functional elements in LSIs, because of their low-power consumption and small size. Whereas, the low driving capability, the lack of compact model, and the oscillating Id-Vg characteristic of SETs make it difficult to use them in LSIs as alternatives of advanced MOSFETs. However, in ubiquitous era, LSIs are expected to be widely used not only in high-performance computers, PCs, PDAs, and cell phones but also in ultra-small electronic devices for various applications such as electronic tags, credit cards, and so on, leading to increased requirements against LSIs in terms of functionality as well as power-consumption. The change is drastic, and the increased requirements might not be fulfilled by conventional MOSFETs. Thus, the change, or the widening, of target applications could offer an opportunity to "new" functional electronic devices such as SETs, which have different functionalities from those of MOSFETs. This paper firstly gives a strategy for using SETs in conventional logic circuits in order to reduce power consumption. The compact modeling of SETs are also discussed. Then, new application domains where SETs could be used by making use of their characteristics, such as high-charge sensitivity and oscillating Td-Vg characteristics are discussed