Walter Houser Brattain
Brattain, Walter Houser (1902-1987), an American physicist, shared the Nobel Prize in physics in 1956 with his colleagues John Bardeen and William Shockley for inventing the transistor, which ushered in the era of microminiature electronic parts and led to today's computers.
Brattain was born in Xiamen, China, where his father, a recent graduate of Whitman College in Walla Walla, Washington, was teaching science and math. The following year, the Brattain family returned to Washington, where Walter and his brother, Robert, spent much of their youth helping out on the family's cattle ranch near the Canadian border. In 1920, he enrolled at Whitman College, where he majored in physics and math. After completing a bachelor's degree in physics at Whitman in 1924, Brattain earned a master's degree at the University of Oregon (1926) and a doctorate degree at the University of Minnesota (1929). Brattain's first job, as a radio engineer at the National Bureau of Standards, left him anxious to return to physics. At a meeting of the American Physical Society, his thesis adviser, John Tate, introduced him to Joseph Becker of the Bell Telephone Laboratories, a major U.S. corporate research center. Becker hired Brattain and he remained at Bell Labs until his retirement in 1967.
Upon arrival at Becker's lab in New York City in summer 1929, Brattain began working with copper-oxide rectifiers. A rectifier is a device for changing alternating current into direct current. Brattain and Becker hoped to use copper-oxide rectifiers to make an amplifier similar in design to a vacuum tube. An amplifier strengthens electrical impulses. A vacuum tube is a tubelike glass or metal shell in which various plates and wires are mounted. The vacuum tube gets its name from the fact that almost all the air must be removed from the tube for it to work.
Although the two researchers did not succeed, Brattain was able to impress the president of Bell Labs, Mervin Kelly. In March 1940, Kelly summoned Brattain and Becker to his office, where he showed them the work of another Bell Labs scientist, Russell Ohl. Ohl had accidentally discovered a mysterious effect that occurred in a cracked silicon crystal. When light was shined on the crystal, the amount of current flowing through the crystal changed. Brattain first thought that he and Becker were the butts of a practical joke, but he quickly came up with an impromptu explanation that proved to be correct: the extra electric current must originate at the crack in the crystal.
Ohl's accidental discovery suggested that vacuum tubes, which were slow to warm up, needed a great deal of power, and were bulky, might be replaced by crystals of silicon and other semiconductors, which did not need to be heated, drew very little current, and were small. Semiconductors are crystalline materials, like silicon and germanium, whose properties of conducting electricity fall between those of conductors (like the copper used in electrical wires) and insulators (like the plastic coatings put on wires).
The military needs of World War II (1939-1945) redirected Brattain's scientific focus for nearly two years, during which he was assigned to study magnetic detection of submarines at the National Defense Research Committee at Columbia University. After the war, he returned to Bell Labs, where he was assigned to a new solid-state research team. Headed by William Shockley, the team also included John Bardeen, a friend of Brattain's brother, Robert. Brattain, with his experimental expertise, and Bardeen, with his theoretical skills, became a formidable research duo.
In December 1947, the efforts of Brattain and Bardeen to develop an amplifier paid off when they successfully collaborated on the first transistor. This half-inch high device—huge by later standards—was called a point-contact transistor. It was crafted by Brattain more or less according to Bardeen's specifications. Although Bardeen had requested two metal contacts separated by the thickness of a sheet of paper, Brattain substituted a single strip of gold foil. After attaching the foil over the point of a plastic triangle, he used a razor blade to create two gold contacts separated by the width of a hair. A spring held the triangle over a crystal of germanium—a hard, metallic, grayish-white element—so that the contacts barely touched the surface. Brattain had placed the crystal itself on a metal plate, which he attached to a source of voltage. The result was the first semiconductor amplifier.
As soon as Brattain turned on the voltage, he observed that when a small current passed through one of the gold contacts, a stronger—or amplified—current emerged from the other contact. When current passed through the contact, electrons left a thin layer along the top of the germanium. Thus, the current created a P-type layer, a layer of material with an abnormally small number of electrons. The layer under the P-type layer in Brattain's transistor had an abnormally large number of electrons. Such a layer is called an N-type layer; and the boundary between a P-type layer and an N-type layer is a P-N junction. A P-N junction is a crucial part of a transistor because current flows across it. At the P-N junction of Brattain's transistor, the small current that passed through the first gold contact was amplified, and a stronger current flowed toward the second gold contact.
In Ohl's crystal, the crack was a P-N junction, and shining the light initiated the current across the junction. Although Brattain and Bardeen's point-contact transistor soon became obsolete, it led to a host of semiconductor devices, including the microprocessor, which can incorporate millions of transistors. Today's computers all use such microprocessors.
Brattain and Bardeen patented the invention in their names. A few weeks later, Shockley announced his invention of the sandwich transistor. Shockley's invention (patented in his name), and the junction transistor that developed from it, turned out to be easier to mass-produce than Brattain and Bardeen's point-contact transistor.
Although Brattain remained in Shockley's transistor group for a few more years, he was usually excluded from the cutting-edge research and soon transferred to another research team. Bardeen and Shockley eventually left Bell Labs, the former to join the faculty of the University of Illinois in 1951, and the latter in 1953 for a position at the California Institute of Technology. Shockley later formed his own company, Shockley Semiconductor, in Silicon Valley. Having gone their separate ways, the three men learned individually in November 1956 that they were jointly awarded that year's Nobel Prize in physics.
In 1967, following his retirement from Bell Labs, Brattain returned full-time to his alma mater, Whitman College, where already five years earlier he had begun to teach an occasional physics course for nonscience majors. Two years earlier, he had also begun to collaborate with Whitman chemistry professor David Frasco. Supported by Battelle Northwest Laboratories of Richland, Washington, Brattain and Frasco conducted investigations of phospholipid bilayers as a model for the surface of living cells.
In 1974, two years after he retired from Whitman, Brattain was elected to the National Inventors Hall of Fame. He died in Seattle, of Alzheimer's disease, at the age of 85.