Net Journal 1
Leading the world in the development and integration of single-electron transistors and bringing breakthrough by the fusion of information technology and nanotechnology
Fukui Takashi, Doctor of Engineering
Director of Research Center for Integrated Quantum Electronics,
Professor of the Graduate School of Information Science and Technology, Hokkaido University,
Division of Electronics for Informatics's Research Group of Integrated Systems Engineering
LSI integration level that has reached the nano region
---- The term "nanotechnology" has become widely known, and research and development in the fields of biotechnology and medical care has attracted particular attention in the last few years. I believe that research has also been active in the field of information technology.
Dr. Fukui: It has been half a century since Jack Kilby developed semiconductor integrated circuits in 1958, and these circuits have made dramatic progress in miniaturization and high integration since then. Today, there is even large-scale integration (LSI) with more than 100 million circuit elements packed into a square centimeter, and the element size has already shifted from microns to nanometers. While the realization of central processing units (CPs) with a gate length of 11 nanometers by 2014 is projected by the semiconductor industry road map, a variety of challenges exist in the production of semiconductor devices in the nano region.
One is the problem of the production process. The microfabrication technology in common use today is referred to as the top-down system, in which circuit patterns are written directly on silicon wafers using lithography technology. It is said that the processing size achievable on an industrial basis is limited to approximately 35 nanometers.
Another is the problem of increased power consumption and heat generation caused by high integration. Since several thousand electrons are involved in one transistor of an ordinary semiconductor device, power consumption is naturally large for LSI, which is loaded with nearly 100 million transistors. The amount of heat generation is also enormous as they are integrated in an area of one square centimeter. Development of a new operating principle different from that of conventional integrated circuits is considered necessary to realize further miniaturization, and nanotechnology is expected to play a leading role in it.
---- The problem of power consumption and heat generation is also related to the global environment and energy resources. What kind of devices can be realized with the new operating principle?
Dr. Fukui: At present, research institutes within and outside Japan are engaged in the development of technology to reduce the current and voltage supplied to LSI, or to reduce the number of electrons involved in the operation of a transistor. The single-electron transistor, which uses only one electron for on-off control, is attracting particular attention. Power consumption is expected to decrease to 1/10,000th that of conventional devices with the realization of this technology.