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Until 1959, all electronic components were discrete: that is, they performed only one function, and many had to be wired together to create a functional circuit. Although a great number of identical discrete transistors could be fabricated on a single wafer, they then had to be cut up and individually packaged in tiny cans. Packaging each component and hand wiring them into circuits was extremely inefficient. People (the military expecially) sought more efficient methods of making circuits.
New technologies emerged and integrated circuits were soon developed with various components (diodes,transistors, resistors, and capacitors) formed on the same chip, but interconnecting the various components still required tedious hand wiring.
In 1959, Jean Hoerni and Robert Noyce developed a new process called planar technology which enabled them to diffuse various layers onto the surface of a silicon wafer to make a transistor, leaving a layer of protective oxide on the junctions. This process allowed metal interconnections to be evaporated onto the flat transistor surface and replaced hand wiring. This new process used silicon instead of germanium, and made commercial production of Integrated circuits possible.
At the same time Jack Kilby was working at Texas Instruments on a problem of great importance. This problem was that of wiring complexity also know as the tyranny of numbers problem. Transistors were able to provide the "switching", rapid on and off signaling, that computers and other electronic devices require. However, problem becomes interesting with more (say millions and billions) of transistors and other parts. Kilby's idea was to use silicon as the capacitor in the circuit. If you can make all parts of the circuit out of one material, then you can manufacture all the parts at once, in a single (often called "monolithic") block of material. Silicon material is more abundant and cheaper (although it is not as good a semiconductor as generanuim). Moreover if all the parts where integrated on a single slice of silicon, you wouldn’t have to wire anything together. The idea was that connections can be laid down internally in the silicon without any need to do any wiring. Suddenly the tyranny of number problems is solved, without wiring or connections an awful lot of components can be fit onto one intregrated circuit. Next he carefully sketched the N and P regions in is notebook and came up with a rough sketched looking like the IC on the right. The first circuit ever designed was a crude resistor made from a strip of pure silicon. Then a bipolar strip of silicon was used to wire the N and P regions to make the capacitor. The test circuit (shown right) was impressive because it worked on the first try. With that a new era in electronics was born. The initial resistance to the new IC technology gave way to enormous popularity. By the end of the 1960s, nearly 90% of all the components manufactured used integrated circuits. Today IC’s are used in almost every facet of our lives for more on the uses of IC’s click here.
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