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Brattain, W

Walter Houser Brattain

Achievements: American scientist who, with colleagues John Bardeen and William Shockley, invented the transistor, for which they were jointly awarded the 1956 Nobel Prize for physics.

Born: February 10, 1902; Amoy, China

Died: October 13, 1987; Seattle, Washington (Aged 85)

Field & Discipline: Science; Physics; Physicist

Language: English

Father: Ross R. Brattain

Mother: Ottilie Houser

Siblings: Four younger siblings

Spouse: 1) Keren Gilmore (m. 1935, d. 1957); 2) Emma Jane Kirsch Miller (m. 1958)

Children: William Gilmore

Education: Tonasket public schools; Whitman College, Washington (1920-24)

Major Work:

"The Transistor: A Semi-Conductor Triode" (with John Bardeen, 1948)

Life & Times:

While completing his doctoral research, Brattain spent a year (1928-29) employed in the radio section of the National Bureau of Standards (NBS), where he worked on improving the accuracy of time and vibration-frequency measurements and helped design a portable temperature-controlled oscillator.

Shortly after receiving his Ph.D. in 1929, he accepted a job as a research physicist with the Bell Telephone Laboratories at Murray Hill, New Jersey, one of the major corporate research centres in the U.S., where he remained until he reached retirement age in 1967.

During his first seven years at Bell Labs, where he became involved in researching ways to improve the three-electrode (triode) vacuum tubes (invented by [improved work of] De Forest* in 1907), then the primary electronic amplifying device, by investigating the effect of adsorbed films on electron emission from hot surfaces.

One major problem with this device was that the high temperature needed to produce electron emission in the triode shortened the life of the electron emitter (cathode) and harmed the vacuum tube.

In 1934, Brattain found that certain thin cathode coatings provided sufficient emissions at reduced temperatures, thus improving amplifier action and prolonging the life of the triode.

The course of Brattain's investigations altered dramatically in 1936 with the arrival at Bell Labs of [collaborated with] Shockley*, who began a programme of research into the properties of a class of materials called semiconductors. Shockley's long-term aim was to replace the bulky three-vacuum-tube devices with solid-state devices that would be smaller, more robust, and more energy efficient.

Shockley knew that semi-conducting material had been used in early crystal radios as a rectifier (a device that changes alternating current to direct current), consisting of a contact between a curl of wire (a "cat's whisker") and a piece of the mineral galena (a semiconductor) to rectify the small signals picked up by antennas from radio waves. Shockley speculated that other kinds of semiconductors might possibly be used both as rectifiers and amplifiers.

He and Brattain set about investigating various semi-conducting materials. During 1938-42, Shockley designed a series of arrangements containing semi-conductors - based on his theory that the current flowing through a semiconductor could be affected by an electric field established by a voltage applied from the outside (the model for what is now known as a field-effect transistor) - which Brattain then constructed and tested. However, to their disappointment they found that none of these arrangements worked as Shockley had predicted.

In 1942, this research was interrupted by World War II, and Brattain and Shockley were both assigned to the Division of War Research at Columbia University in order to work on devices for the magnetic detection of submarines. In 1945 they both returned to Bell Labs, where they were joined by [collaborated with] Bardeen*, a theoretical physicist, who, having studied their previous experiments, suggested that the earlier failures might be due to an accumulation of electrons trapped on the surface of the semiconductor which was preventing the electric field from entering its body.

As a result of this suggestion, the team initiated an extensive study of semiconductor surfaces, which were subjected to light, heat, cold, and the application of liquids and metallic films. In late 1947, with much improved knowledge of semi-conductor surfaces, Brattain and Bardeen constructed the first point-contact transistor.

This device consisted of two closely spaced (0.005 cm apart) gold contacts (the emitter and collector) on one face of a block of germanium crystal and a third contact (the base) on the opposite side; when an electrical signal was fed into one side of the crystal, it was emitted on the opposite side,  amplified eighteen times.

Brattain and Bardeen wrote a paper outlining their achievement entitled "The Transistor: A Semi-Conductor Triode", which was published in the journal 'Physical Review' in 1948, but generally the news was greeted with little interest.

Meanwhile, Shockley had predicted that the new device, which they named a transistor (short for "transfer resistor"), could be greatly improved by replacing the metal semiconductor contacts with rectifying contacts placed between two different kinds of semiconductors.

These semiconductor materials "doped" with small amounts of specific impurities that either produce a surplus of electrons (known as N-type [electron surplus] semiconductors) which are therefore available to participate in a current, or produce a deficiency of electrons, creating spaces left by missing electrons known as "holes" (known as a P-type [electron deficient] semiconductors).

A successful model of this new "junction transistor" was made by Brattain and Bardeen in 1950, consisting of a thin P-type region sandwiched between two N-type regions, with metallic contacts to each region. The junction transistor proved much easier to produce and far superior in performance when compared with the point-contact type, and it quickly replaced it in most applications.

A practical field-effect transistor was eventually made using silicon crystals (which are more resistant to high temperatures), once crystal-growing and purifying techniques were sufficiently advanced, and is now the basic design used electronic devices.

In 1956 Brattain, Bardeen and Shockley were jointly awarded the Nobel Prize for physics "for their research on semiconductors and their discovery of the transistor effect".  Brattain emphasized the importance of the atomic properties of surfaces (which usually differs from the atomic structure in the interior of a material) in his Nobel lecture, "Surface Properties of Semiconductors", and much of his subsequent work at Bell Labs, where he remained until his

retirement in 1967, was concerned with the properties of semiconductors and their surfaces.

This research proved of great importance to the development of silicon field-effect transistors, which are extremely susceptible to surface defects, and to solar cells, which are sensitive to surface electrical behaviour.

Extra Connections:  Some of his work was anticipated by [anticipated by] Braun*

Assessment:  Had a profound effect on the application of electronics.

Oneliner:  Walter Brattain, co-inventor of the transistor

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