The first planar monolithic integrated circuit (IC) chip was demonstrated in 1960. The idea of integrating electronic circuits into a single device was born when the German physicist and engineer Werner Jacobi developed and patented the first known integrated transistor amplifier in 1949 and the British radio engineer Geoffrey Dummer proposed to integrate a variety of standard electronic components in a monolithic semiconductor crystal in 1952. A year later, Harwick Johnson filed a patent for a prototype IC. Between 1953 and 1957, Sidney Darlington and Yasuo Tarui (Electrotechnical Laboratory) proposed similar chip designs where several transistors could share a common active area, but there was no electrical isolation to separate them from each other.

These ideas could not be implemented by the industry, until a breakthrough came in late 1958. Three people from three U.S. companies solved three fundamental problems that hindered the production of integrated circuits. Jack Kilby of Texas Instruments patented the principle of integration, created the first prototype ICs and commercialized them. Kilby's invention was a hybrid integrated circuit (hybrid IC), rather than a monolithic integrated circuit (monolithic IC) chip. Between late 1958 and early 1959, Kurt Lehovec of Sprague Electric Company developed a way to electrically isolate components on a semiconductor crystal, using p–n junction isolation.

The first monolithic IC chip was invented by Robert Noyce of Fairchild Semiconductor. He invented a way to connect the IC components (aluminium metallization) and proposed an improved version of insulation based on the planar process technology developed by Jean Hoerni. On September 27, 1960, using the ideas of Noyce and Hoerni, a group of Jay Last's at Fairchild Semiconductor created the first operational semiconductor IC. Texas Instruments, which held the patent for Kilby's invention, started a patent war, which was settled in 1966 by the agreement on cross-licensing.

There is no consensus on who invented the IC. The American press of the 1960s named four people: Kilby, Lehovec, Noyce and Hoerni; in the 1970s the list was shortened to Kilby and Noyce. Kilby was awarded the 2000 Nobel Prize in Physics "for his part in the invention of the integrated circuit". In the 2000s, historians Leslie Berlin, Bo Lojek and Arjun Saxena reinstated the idea of multiple IC inventors and revised the contribution of Kilby. Modern IC chips are based on Noyce's monolithic IC, rather than Kilby's hybrid IC.

Prerequisites

Waiting for a breakthrough

During and immediately after World War II a phenomenon named "the tyranny of numbers" was noticed, that is, some computational devices reached a level of complexity at which the losses from failures and downtime exceeded the expected benefits. Each Boeing B-29 (put into service in 1944) carried 300–1000 vacuum tubes and tens of thousands of passive components. The number of vacuum tubes reached thousands in advanced computers and more than 17,000 in the ENIAC (1946). Each additional component reduced the reliability of a device and lengthened the troubleshooting time. Traditional electronics reached a deadlock and a further development of electronic devices required reducing the number of their components.

The invention of the first transistor in 1947 led to the expectation of a new technological revolution. Fiction writers and journalists heralded the imminent appearance of "intelligent machines" and robotization of all aspects of life. Although transistors did reduce the size and power consumption, they could not solve the problem of reliability of complex electronic devices. On the contrary, dense packing of components in small devices hindered their repair. While the reliability of discrete components was brought to the theoretical limit in the 1950s, there was no improvement in the connections between the components.

Idea of integration

Early developments of the integrated circuit go back to 1949, when the German engineer Werner Jacobi (Siemens AG) filed a patent for an integrated-circuit-like semiconductor amplifying device showing five transistors on a common substrate in a 3-stage amplifier arrangement with two transistors working "upside-down" as impedance converter. Jacobi disclosed small and cheap hearing aids as typical industrial applications of his patent. An immediate commercial use of his patent has not been reported.

On May 7, 1952, the British radio engineer Geoffrey Dummer formulated the idea of integration in a public speech in Washington:

Dummer later became famous as "the prophet of integrated circuits", but not as their inventor. In 1956 he produced an IC prototype by growth from the melt, but his work was deemed impractical by the UK Ministry of Defence, because of the high cost and inferior parameters of the IC compared to discrete devices.

In May 1952, Sidney Darlington filed a patent application in the United States for a structure with two or three transistors integrated onto a single chip in various configurations; in October 1952, Bernard Oliver filed a patent application for a method of manufacturing three electrically connected planar transistors on one semiconductor crystal.

On May 21, 1953, Harwick Johnson filed a patent application for a method of forming various electronic components – transistors, resistors, lumped and distributed capacitances – on a single chip. Johnson described three ways of producing an integrated one-transistor oscillator. All of them used a narrow strip of a semiconductor with a bipolar transistor on one end and differed in the methods of producing the transistor. The strip acted as a series of resistors; the lumped capacitors were formed by fusion whereas inverse-biased p-n junctions acted as distributed capacitors. Johnson did not offer a technological procedure, and it is not known whether he produced an actual device. In 1959, a variant of his proposal was implemented and patented by Jack Kilby.

In 1957, Yasuo Tarui, at MITI's Electrotechnical Laboratory near Tokyo, fabricated a "quadrupole" transistor, a form of unipolar (field-effect transistor) and a bipolar junction transistor on the same chip. These early devices featured designs where several transistors could share a common active area, but there was no electrical isolation to separate them from each other.

Functional electronics The leading US electronics companies (Bell Labs, IBM, RCA and General Electric) sought solution to "the tyranny of numbers" in the development of discrete components that implemented a given function with a minimum number of attached passive elements. During the vacuum tube era, this approach allowed to reduce the cost of a circuit at the expense of its operation frequency. For example, a memory cell of the 1940s consisted of two triodes and a dozen passive components and ran at frequencies up to 200 kHz. A MHz response could be achieved with two pentodes and six diodes per cell. This cell could be replaced by one thyratron with a load resistor and an input capacitor, but the operating frequency of such circuit did not exceed a few kHz.

In 1952, Jewell James Ebers from Bell Labs developed a prototype solid-state analog of thyratron – a four-layer transistor, or thyristor. William Shockley simplified its design to a two-terminal "four-layer diode" (Shockley diode) and attempted its industrial production. Shockley hoped that the new device would replace the polarized relay in telephone exchanges; however, the reliability of Shockley diodes was unacceptably low, and his company went into decline.

At the same time, works on thyristor circuits were carried at Bell Labs, IBM and RCA. Ian Munro Ross and L. Arthur D'Asaro (Bell Labs) experimented with thyristor-based memory cells. Joe Logue and Rick Dill (IBM) were building counters using monojunction transistors. J. Torkel Wallmark and Harwick Johnson (RCA) used both the thyristors and field-effect transistors. The works of 1955–1958 that used germanium thyristors were fruitless. Only in the summer of 1959, after the inventions of Kilby, Lehovec and Hoerni became publicly known, D'Asaro reported an operational shift register based on silicon thyristors. In this register, one crystal containing four thyristors replaced eight transistors, 26 diodes and 27 resistors. The area of each thyristor ranged from 0.2 to 0.4 mm2, with a thickness of about 0.1 mm. The circuit elements were isolated by etching deep grooves.

From the point of view of supporters of functional electronics, semiconductor era, their approach was allowed to circumvent the fundamental problems of semiconductor technology. The failures of Shockley, Ross and Wallmark proved the fallacy of this approach: the mass production of functional devices was hindered by technological barriers.

Silicon technology

Early transistors were made of germanium. By the mid-1950s this was replaced by silicon which could operate at higher temperatures. In 1954, Gordon Kidd Teal from Texas Instruments produced the first silicon transistor, which became commercial in 1955. Also in 1954, Fuller and Dittsenberger published a fundamental study of diffusion in silicon, and Shockley suggested using this technology to form p-n junctions with a given profile of the impurity concentration.

In early 1955, Carl Frosch from Bell Labs developed wet oxidation of silicon, and further research by Frosch, Moll, Fuller and Holonyak was conducted over the next two years. Later in 1958, Frosch and Lincoln Derick proposed that silicon oxide layers could protect silicon surfaces during diffusion processes, and could be used for diffusion masking. This accidental discovery revealed the second fundamental advantage of silicon over germanium: contrary to germanium oxides, "wet" silica is a physically strong and chemically inert electrical insulator.

Surface passivation

Surface passivation, the process by which a semiconductor surface is rendered inert, and does not change semiconductor properties as a result of interaction with air or other materials in contact with the surface or edge of the crystal, was first developed by Mohamed Atalla at Bell Labs, in 1957. Atalla discovered that the formation of a thermally grown silicon dioxide () layer greatly reduced the concentration of electronic states at the silicon surface, and discovered the important quality of films to preserve the electrical characteristics of p–n junctions and prevent these electrical characteristics from deteriorating by the gaseous ambient environment. He found that silicon oxide layers could be used to electrically stabilize silicon surfaces. He developed the surface passivation process, a new method of semiconductor device fabrication that involves coating a silicon wafer with an insulating layer of silicon oxide so that electricity could reliably penetrate to the conducting silicon below. By growing a layer of silicon dioxide on top of a silicon wafer, Atalla was able to overcome the surface states that prevented electricity from reaching the semiconducting layer.

At a 1958 Electrochemical Society meeting, Atalla presented a paper about the surface passivation of p-n junctions by thermal oxidation, based on his 1957 memos, and demonstrated silicon dioxide's passivating effect on a silicon surface. This was the first demonstration to show that high-quality silicon dioxide insulator films could be grown thermally on the silicon surface to protect the underlying silicon p-n junction diodes and transistors. By the mid-1960s, Atalla's process for oxidized silicon surfaces was used to fabricate virtually all integrated circuits and silicon devices.

Planar process