Beyond CMOS

The slow but inevitable approach of the technological limit to CMOS has produced a steady increase in research into alternative or complementary devices and technologies. There is a wide spread in the maturity of this research and development, starting with relatively mature technologies such as MRAM or resonant tunneling diodes and rapid single flux quanta (RSFQ) systems. More speculative prospects include single-walled carbon nanotube (SWCNT) transistors and logic gates and the even more speculative molecular transistor devices. On an even longer timescale there hovers the prospect of quantum computing systems. It is important to try to assess the chances of any of these device technologies ever taking over from CMOS. The author discusses the problems these devices face. Additionally, all of the increasing research into nanoelectronics is helping to clarify which devices might or might not work. The study of nanoscale phenomena will help with the development of more robust devices and systems. More fundamental is the fact that there is still much room for manouver in nanoscale and mesoscale device technology: Examples will be presented to show how this design flexibility can be exploited.