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Integrated circuits developed from transistor
technology as scientists sought ways to build more transistors
into a circuit. The first integrated circuits were patented in
1959
by two Americans-Jack
Kilby, an
engineer, and
Robert Noyce,
a physicist-who worked independently. Integrated circuits had
caused a great revolution in electronics in the 1960's as
transistors had caused in 1950's. The circuits were first used
in military equipment and space craft and helped make possible
the first human space flights of the 1960's. They were soon
being
3
used in
household electronic products, such as sewing machines,
microwave ovens, and television sets.
Most integrated circuits are small pieces, or
“chips,” of silicon, perhaps (0.08 to 0.15 sq in) long, in which
transistors are fabricated. Photolithography enables the
designer to create tens of thousands of transistors on a single
chip by proper placement of the many n-type and p-type regions.
These are interconnected with very small conducting paths during
fabrication to produce complex special-purpose circuits. Such
integrated circuits are called monolithic because they are
fabricated on a single crystal of silicon. Chips require much
less space and power and are cheaper to manufacture than an
equivalent circuit built by employing individual transistors.
Integrated circuits (ICs) make the microcomputer possible;
without them, individual circuits and their components would
take up far too much space for a compact computer design. The
typical IC consists of elements such as resistors, capacitors,
and transistors packed on a single piece of silicon. In smaller,
more densely packed ICs, circuit elements may be only a few
atoms in size, which makes it possible to create sophisticated
computers the size of notebooks. A typical computer circuit
board features many integrated circuits connected together.
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