The building block of the computer revolution in the 1970s and the basis of today's multibillion-dollar computer industry is the computer chip. Usually about one-third of an inch square, these chips are the "brains" critical to many sophisticated and not-so-sophisticated devices such as calculators, appliances, televisions and radios. They also have great importance in areas of environmental monitoring, medicine, automobiles and other vehicles, and traffic control. They have greatly reduced the size and cost of most electronic products, while at the same time increasing their power and versatility.

Computer chips are integrated circuits called microprocessors built up from transistors and other components. Transistors are small binary electrical switches. Transistors have no moving parts and are switched between their two allowed states, "on" and "off", electronically. Microprocessors are fabricated on a single crystal of a semiconducting material such as silicon or germanium. A semiconductor is a substance...