Abstract
For the last four decades the miniaturization of the microchip has been the driving force behind developments in all kinds of technology, from home entertainment to space exploration. At the heart of this revolution lies the metal-oxide-semiconductor (MOS) transistor, which has evolved in two ways. First, it has become smaller, with the latest devices measuring a thousandth of their original size. Second, the number of transistors that can be interconnected on a single chip has risen from a few tens to hundreds of millions.