integrated circuit(redirected from Computer chips)
Also found in: Dictionary, Thesaurus, Medical.
Related to Computer chips: silicon chip
integrated circuit(IC), electronic circuit built on a semiconductorsemiconductor,
solid material whose electrical conductivity at room temperature is between that of a conductor and that of an insulator (see conduction; insulation). At high temperatures its conductivity approaches that of a metal, and at low temperatures it acts as an insulator.
..... Click the link for more information. substrate, usually one of single-crystal silicon. The circuit, often called a chip, is packaged in a hermetically sealed case or a nonhermetic plastic capsule, with leads extending from it for input, output, and power-supply connections, and for other connections that may be necessary when the device is put to use. Integrated circuits can be classified into two groups based on the type of transistorstransistor,
three-terminal, solid-state electronic device used for amplification and switching. It is the solid-state analog to the triode electron tube; the transistor has replaced the electron tube for virtually all common applications.
..... Click the link for more information. they contain. Bipolar integrated circuits contain bipolar junction transistors as their principle elements. Metal-oxide-semiconductor (MOS) integrated contain MOS transistors as their principle elements. Some integrated circuits contain both types of transistors. Integrated circuits are also categorized according to the number of transistors or other active circuit devices they contain. An IC is said to use small-scale integration (SSI) if it contains fewer than 10 transistors. An IC that contains from 10 to 100 transistors is said to use medium-scale integration. A large-scale integration (LSI) IC contains from 100 to 1,000 transistors, and one that uses very-large-scale integration (VLSI) contains more than 1,000 transistors. All ICs now employ VLSI, and these distinctions are only of historical importance. Some integrated circuits are analog devices; an operational amplifieroperational amplifier,
amplifier whose output voltage is proportional to the negative of its input voltage and that boosts the amplitude of an input signal many times, i.e., has a very high gain. It is usually connected so that part of the output is fed back to the input.
..... Click the link for more information. is an example. Other ICs, such as the microprocessors used in computerscomputer,
device capable of performing a series of arithmetic or logical operations. A computer is distinguished from a calculating machine, such as an electronic calculator, by being able to store a computer program (so that it can repeat its operations and make logical
..... Click the link for more information. , are digital devices. Some hybrid integrated circuits contain both analog and digital circuitry; a bilateral switch, which switches analog signals by means of a digital control signal is an example of a hybrid IC. Integrated circuit functions are virtually limitless. Improvements in IC manufacturing have led to increasingly dense and capable integrated circuits. Some microprocessors, for example, contain more than one billion transistors on their chips. The smaller, denser chips can also provide speed benefits, because in high-speed devices, the length of time it takes a signal to travel a given distance can become a factor. The major fabricating steps for integrated circuits include film formation, impurity doping, photolithography, etching, and packaging. See microelectronicsmicroelectronics,
branch of electronic technology devoted to the design and development of extremely small electronic devices that consume very little electric power. Although the term is sometimes used to describe discrete electronic components assembled in an extremely small
..... Click the link for more information. .
See M. S. Malone, The Microprocessor: A Biography (1995).
(also integrated microcircuit), a microminiaturized electronic device, all or some of whose components are inseparably structurally linked and are interconnected electrically. There are two basic types: semiconductor integrated circuits and thin-film integrated circuits.
Semiconductor integrated circuits (Figure 1) are manufactured from extremely pure semiconductor materials (usually silicon or germanium), whose crystal lattice is modified in such a way that individual regions of a crystal become components of a complex circuit. A small chip of crystalline material, with an area of about 1 sq mm, becomes a very complex electronic device, equivalent to a radio engineering unit of 50–100 or more conventional components. Such a device is capable of amplifying or generating signals and of functioning in many other radio engineering applications.
The manufacturing technology of semiconductor integrated circuits makes possible the simultaneous multiple production of large numbers of circuits. This determines the identity of circuit properties. Semiconductor circuits have high reliability because of the use of the planar manufacturing process and a significant reduction in the number of microscopic connections of components in the manufacturing process.
Semiconductor integrated circuits are developing in the direction of increasing concentration of components in the same volume of semiconductor crystal (toward a higher degree of integration). Integrated circuits with hundreds and thousands of components in a single crystal have been developed. In such a case an integrated circuit becomes a complex integrated system. Such a system can be developed and manufactured only with the aid of high-output electronic computers.
Thin-film integrated circuits are made by deposition of various materials at a low pressure (on the order of l X 105 mm of mercury [mm Hg]) as thin films (less than 1 micron [M] thick) or thick films (more than 1 μ thick). The film is deposited on a polished substrate, usually a ceramic, that has been preheated to a particular temperature. Materials used for the film include aluminum, gold, titanium, nichrome, tantalum oxide, silicon monoxide, barium titanate, and tin oxide. To produce integrated circuits with specific functions, multilayer thin-film structures are created by deposition of materials with the required properties on the substrate through a mask or stencil. In such structures one of the layers contains microresistors, another layer contains microcapacitors, and several other layers contain interconnecting current conductors and other components. All components in these layers are interconnected in an arrangement characteristic of the particular electronic device.
Thin-film components are widely used in hybrid integrated circuits (Figure 2). In such systems the passive components (resistors, capacitors, and conductors) are deposited first on the substrate as thin or thick films, and then the active semiconductor microcomponents (nude transistors and diodes) are mounted with the aid of micromanipulators.
Semiconductor and hybrid integrated circuits are complementary in terms of design and electrical characteristics; they can be used simultaneously in identical radioelectronic units. Integrated circuits are mounted in casings that protect them from external influences. Integrated circuits are categorized according to the number of components: first degree of integration (up to 10 components), second degree of integration (10–100), and so on.
The dimensions of the individual components of an integrated circuit are very small (on the order of 0.5-10.Oμ) and are sometimes commensurate with the dimensions of dust particles (1–100 μ). Therefore, the manufacture of integrated circuits is conducted under extremely clean conditions.
There are several trends in the design of integrated circuits, including hybrid circuits, with discrete active components; semiconductor circuits made in a single block of semiconductor material; combined circuits, in which the active components are made in a single block of semiconductor material and the passive components are deposited as thin films; and thin-film circuits, where both the active and passive components are deposited on the substrate as thin films.
REFERENCESKolosov, A. A., Iu. I. Gorbunov, and Iu. E. Naumov. Poluprovodnikovye tverdye schemy. Moscow, 1965.
Integral’nye skhemy: Prinlsipy konslruirovaniia iproizvodstva. Edited by A. A. Kolosov. Moscow, 1968. (Translated from English.)
Integral’nye skhemy: Osnovy proektirovaniia i technologii. Edited by K. I. Martiushov. Moscow, 1970. (Translated from English.)
I. E. EFTMOV
integrated circuit[′int·ə‚grād·əd ′sər·kət]
Integrated circuits can be classified into analogue, digital and hybrid (both analogue and digital on the same chip). Digital integrated circuits can contain anything from one to millions of logic gates - inverters, AND, OR, NAND and NOR gates, flip-flops, multiplexors etc. on a few square millimeters. The small size of these circuits allows high speed, low power dissipation, and reduced manufacturing cost compared with board-level integration.
The first integrated circuits contained only a few transistors. Small Scale Integration (SSI) brought circuits containing transistors numbered in the tens. Later, Medium Scale Integration (MSI) contained hundreds of transistors. Further development lead to Large Scale Integration (LSI) (thousands), and VLSI (hundreds of thousands and beyond). In 1986 the first one megabyte RAM was introduced which contained more than one million transistors.
LSI circuits began to be produced in large quantities around 1970 for computer main memories and pocket calculators. For the first time it became possible to fabricate a CPU or even an entire microprocesor on a single integrated circuit. The most extreme technique is wafer-scale integration which uses whole uncut wafers as components.
integrated circuitThe formal name for the chip. In 1958, Texas Instruments inventor Jack Kilby demonstrated the first electronic circuit in which more than one transistor was fabricated on a single piece of semiconductor material. See chip.
|The First Integrated Circuit|
|About a half inch wide, this archaic-looking collection of two transistors mounted on a bar of germanium was nonetheless the first integrated circuit. It was demonstrated by TI on September 12, 1958. (Image courtesy of Texas Instruments, Inc.)|
|Seven Years Later|
|This amplifier circuit from Siemens was mass produced in 1965. Containing three transistors and five resistors on a 1.5 square millimeter chip, it was a world of sophistication compared to the two-transistor breakthough seven years earlier. (Image courtesy of Siemens AG, www.siemens.com)|