MICROFABRICATION AND MOORE’S LAW

Microfabrication and Moore’s law

The top-down approach to microelectronics seems to be governed by exponential time dependence. I 1965, when the most advanced integrated circuit contained only 64 transistors, Gordon E. Moore, Director of Fairchild Semiconductor Division, was the first to note this exponential behavior in his famous paper Cramming more components onto integrated circuits [Electronics, 38, No. 8, April 19 (1965)]: ”When unit cost is falling as the number of components per circuit rises, by 1975 economics may dictate squeezing as many as 65,000 components on a single silicon chip”. He observed a doubling of the number of transistors per circuit every year, a law that has become known as Moore’s law. Today there exist many other versions of Moore’s law. It concerns the exponential decrease in the length of the gate electrode in standard CMOS transistors, and relates to the previous quoted values of 90 nm in 2003 and 65 nm in 2005. Naturally, there will be physical limitations to the exponential behavior expressed in Moore’s law, see Exercise 1.1. However, also economic barriers play a major if not the decisive role in ending Moore’s law developments. The price for constructing microprocessor fabrication units also rises exponentially for each generation of microchips.