Integrated circuit

An integrated circuit (IC) is a thin chip consisting of at least two interconnected semiconductor devices, mainly transistors, as well as passive components like resistors. As of 2004, typical chips are of size 1 cm2 or smaller, and contain millions of interconnected devices, but larger ones exist as well.

History; origins and generations

The birth of the IC

The integrated circuit was first conceived by a radar scientist, Geoffrey W.A. Dummer (born 1909), working for the Royal Radar Establishment of the British Ministry of Defence, and published in Washington DC on May 7, 1952. Dummer unsuccessfully attempted to build such a circuit in 1956.

Related Topics:
Geoffrey W.A. Dummer - Ministry of Defence - Washington DC - May 7 - 1952

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The first integrated circuits were manufactured independently by two scientists: Jack Kilby of Texas Instruments filed a patent for a "Solid Circuit" made of germanium on February 6, 1959. Kilby received patents US3138743, US3138747, US3261081, and US3434015. Robert Noyce of Fairchild Semiconductor was awarded a patent for a more complex "unitary circuit" made of Silicon on April 25, 1961. (See the Chip that Jack built for more information.)

Related Topics:
Jack Kilby - Texas Instruments - Germanium - February 6 - 1959 - Robert Noyce - Fairchild Semiconductor - April 25 - 1961

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Noyce credited Kurt Lehovec of Sprague Electric for the principle of p-n junction isolation caused by the action of a biased p-n junction (the diode) as a key concept behind the IC.{{fn|Lehovec}}

Related Topics:
Kurt Lehovec - Sprague Electric - P-n junction

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SSI, MSI, LSI

The first integrated circuits contained only a few transistors. Called "Small-Scale Integration" (SSI), they used circuits containing transistors numbering in the tens.

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SSI circuits were crucial to early aerospace projects, and vice-versa. Both the Minuteman missile and Apollo program needed lightweight digital computers for their inertially-guided flight computers; the Apollo guidance computer led and motivated the integrated-circuit technology, while the Minuteman missile forced it into mass-production.

Related Topics:
Minuteman missile - Apollo program - Apollo guidance computer

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These programs purchased almost all of the available integrated circuits from 1960 through 1963, and almost alone provided the demand that funded the production improvements to get the production costs from $1000/circuit (in 1960 dollars) to merely $25/circuit (in 1963 dollars).

Related Topics:
1960 - 1963

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The next step in the development of integrated circuits, taken in the late 1960s, introduced devices which contained hundreds of transistors on each chip, called "Medium-Scale Integration" (MSI).

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They were attractive economically because while they cost little more to produce than SSI devices, they allowed more complex systems to be produced using smaller circuit boards, less assembly work (because of fewer separate components), and a number of other advantages.

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Further development, driven by the same economic factors, led to "Large-Scale Integration" (LSI) in the mid 1970s, with tens of thousands of transistors per chip.

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LSI circuits began to be produced in large quantities around 1970, for computer main memories and pocket calculators.

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VLSI

The final step in the development process, starting in the 1980s and continuing on, was "Very Large-Scale Integration" (VLSI), with hundreds of thousands of transistors, and beyond (well past several million in the latest stages).

Related Topics:
1980s - VLSI

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For the first time it became possible to fabricate a CPU on a single integrated circuit, to create a microprocessor. In 1986 the first one megabit RAM chips were introduced, which contained more than one million transistors. Microprocessor chips produced in 1994 contained more than three million transistors.

Related Topics:
CPU - Microprocessor - 1986 - RAM - 1994

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This step was largely made possible by the codification of "design rules" for the CMOS technology used in VLSI chips, which made production of working devices much more of a systematic endeavour. (See the 1980 landmark text by Carver Mead and Lynn Conway referenced below.)

Related Topics:
CMOS - Carver Mead - Lynn Conway

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ULSI, WSI, SOC

To reflect further growth of the complexity, the term ULSI that stands for "Ultra-Large Scale Integration" was proposed for chips of complexity more than 1 million of transistors. However there is no qualitative leap between VLSI and ULSI, hence normally in technical texts the "VLSI" term covers ULSI as well, and "ULSI" is reserved only for cases when it is necessary to emphasize the chip complexity, e.g., in marketing.

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The most extreme integration technique is wafer-scale integration (WSI), which uses whole uncut wafers containing entire computers (processors as well as memory). Attempts to take this step commercially in the 1980s (e.g. by Gene Amdahl) failed, mostly because of defect-free manufacturability problems, and it does not now seem to be a high priority for industry.

Related Topics:
1980s - Gene Amdahl

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The WSI technique failed commercially, but advances in semiconductor manufacturing allowed for another attack on the IC complexity, known as System-on-Chip (SOC) design. In this approach, components traditionally manufactured as separate chips to be wired together on a printed circuit board, are designed to occupy a single chip that contains memory, microprocessor(s), peripheral interfaces, Input/Output logic control, data converters, etc., i.e., the whole electronic system.

Related Topics:
System-on-Chip - Printed circuit board

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