d by business, university, and government establishments. They had not yet been passed down to the general public. The real part of the computer revolution was about to begin. One of the most abundant elements in the earth is silicon; a non-metal substance found in sand as well as in most rocks and clay. The element has given rise to the name “Silicon Valley” for Santa Clara County, about 50 km south of San Francisco. In 1965, Silicon valley became the principle site of the computer industry, making the so-called silicon chip. An integrated circuit is a complete electronic circuit on a small chip of silicon. The chip may be less than 3mm square and contain hundreds to thousands of electronic components. Beginning in 1965, the integrated circuit began to replace the transistor in machines was now called third-generation computers. An Integrated Circuit was able to replace an entire circuit board of transistors with one chip of silicon much smaller than one transistor. Silicon is used because it is a semiconductor. It is a crystalline substance that will conduct electric current when it has been doped with chemical impurities shot onto the structure of the crystal. A cylinder of silicon is sliced into wafers, each about 76mm in diameter. The wafer is then etched repeatedly with a pattern of electrical circuitry. Up to ten layers may be etched onto a single wafer. The wafer is then divided into several hundred chips, each with a circuit so small it is half the size of a fingernail; yet under a microscope, it is complex as a railroad yard. A chip 1 centimeter square it is so powerful that it can hold 10,000 words, about the size of an average newspaper. Integrated circuits entered the market with the simultaneous announcement in 1959 by Texas Instruments and Fairchild Semicon...
