The Idea Factory: Bell Labs and the Great Age of American Innovation (12 page)

Essentially Kelly was creating interdisciplinary groups—combining chemists, physicists, metallurgists, and engineers; combining theoreticians with experimentalists—to work on new electronic technologies. But putting young men like Shockley in a management position devastated some of the older Labs scientists. Addison White, a younger member of the technical staff who before the war had taken part in Shockley’s weekly study group, told Hoddeson he nevertheless considered it “a stroke of enormously good management on Kelly’s part.” He even thought it an act of managerial bravery to strip the titles from men Kelly had worked with for decades. “One of these men wept in my office after this happened,” White said. “I’m sure it was an essential part of what by this time had become a revolution.”
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No documentation, and no private papers, have ever surfaced to fully explain Kelly’s rationale.
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Was he at this point looking for an actual invention that he could now clearly articulate, or was he just acting on a hunch that something useful was waiting to be found, and that if it weren’t something big, then surely combining men of such talent in a state-of-the-art building would produce a breakthrough? There exists
only one true founding document of the revolution: an authorization form that Kelly signed to fund the new groups he had organized. Under Bell System protocol, work at Bell Labs had to be billed to either AT&T, Western Electric, or the local operating companies like Pacific Telephone. Different types of research were classified as a “case,” and each case was in turn approved (or, rarely, challenged) by corporate management. Vacuum tube development, for instance, had its own case number, as did basic physics research. This was one reason why Kelly had quashed Fisk’s swimming pool requisition: It could hardly be justified under an existing case number, and even if it could, a new case for building a swimming pool was bound to be met at AT&T headquarters with a skepticism rivaling Kelly’s own.

On June 21, 1945, Kelly had signed off on Case 38139. “A unified approach to all of our solid state problems offers great promise,” he wrote. “Hence all of the research activity in the area of solids is now being consolidated in order to achieve the unified approach to the theoretical and experimental work of the solid state area.” The point of the new effort, in case it was hard to see through the jargon, was “the obtaining of new knowledge that can be used in the development of completely new and improved components” of communications systems. At the end of the six-page document, Kelly noted that he did not anticipate that the solid-state work would bring immediate results to the telephone business. On the other hand, he reasoned, the research was “so basic and may well be of such far-reaching importance” to the business that it was imperative that the phone company supply the funding. The initial cost of the program was put at $417,000, most of which comprised salaries for the group members. The authorization was signed by Harvey Fletcher, Jim Fisk, and Kelly himself. It was billed to AT&T.
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One by one, meanwhile, the men who had left West Street for some military reason or another—for the battlefields, for work in Washington, for a stint in Whippany or at the biscuit building in Manhattan to design radar sets—were filtering back. Walter Brattain had spent the first half of the war working in Washington on submarine detection and the second half at Bell Labs working on other matters of military engineering.
In Kelly’s new order, he would be joining a solid-state research group led mainly by Bill Shockley. The notebook Brattain had used to chart his semiconductor experiments before the war—notebook number 18194—had its last entry in West Street on November 7, 1941. Four years later, in the new Murray Hill building, Brattain picked it up again and opened to page 40. “The war is over,” he wrote.
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I
N LATER YEARS
, it would become a kind of received wisdom that many of the revolutionary technologies that arose at Bell Labs in the 1940s and 1950s owed their existence to dashing physicists such as Bill Shockley, and to the iconoclastic ideas of quantum mechanics. These men could effectively see into the deepest recesses of the atom, and could theorize inventions no one had previously deemed possible. More fundamentally, however, the coming age of technologies owed its existence to a quiet revolution in materials. Indeed, without new materials—that is, materials that were created through new chemistry techniques, or rare and common metals that could now be brought to a novel state of ultrapurity by resourceful metallurgists—the actual physical inventions of the period might have been impossible. Shockley would have spent his career trapped in a prison of elegant theory.

A few of the scientists at Bell Labs grasped the fact earlier than others. Just as the men in Thomas Edison’s old laboratory would tinker with animal hoofs and horsehair in their inventions, for the first three or four decades of the phone system its engineers worked mostly with everyday substances—wooden blocks hewn from the finest bird’s-eye maple to mount switching equipment, or a natural latex known as gutta-percha for waterproofing cables. Increasingly, however, new ideas, and new projects, ran up against the limitation of nature’s design. “We had such specific requirements that ordinary raw materials had an agonizing time meeting them,” William Baker, who joined the Labs as a chemist just before World War II, explained.
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The solution, as Baker described it, was to literally create new types of matter. When the Labs’ chemists needed to help design impermeable underwater cables, for example, one
possibility was gutta-percha. But gutta-percha had drawbacks, including its extreme expense. For an undersea cable to Catalina Island, off the coast of California, the Labs’ chemists began looking for an alternative. Natural rubber was considered too soft in its pure state, and when it was treated with sulfur to toughen it—that is, to “vulcanize” it—the men had to address the problem that sulfur corrodes copper and would undoubtedly degrade the vital wires within the undersea cable. Only after the chemists determined that they could purify the rubber in a complex manner and then create fine silica flour as an insulator could the cable go into production.

Those working with metals wrestled with challenges similar to those working with rubber and plastics. During the Labs’ early days, while Mervin Kelly was running the tube shop in lower Manhattan, metallurgists began to focus on whether special coatings on metal filaments inside the vacuum tubes could vastly improve their performance or durability. The work required them to delve into the uses of obscure elements and alloys, and to conceive—successfully—of arcane processes to heat and cool their mixtures. A similar example arose when Labs scientists tried to improve the thin diaphragm in a phone receiver—the metal disc that vibrates in response to a speaker’s voice. They ultimately created something called Permendur, an alloy of cobalt and iron that was spiced with around 2 percent of the element vanadium. But the metallurgists soon realized that Permendur was only part of the solution to finding a better diaphragm. If the ingredients in the alloy weren’t pure—if they happened to contain minute traces of carbon, oxygen, or nitrogen, for instance—Permendur would be imperfect.
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“There was a time not so long ago when a thousandth of a percent or a hundredth of a percent of a foreign body in a chemical mixture was looked upon merely as an incidental inclusion which could have no appreciable effect on the characteristics of the substance,” Frank Jewett, the first president of the Labs, explained. “We have learned in recent years that this is an absolutely erroneous idea.”
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It was understandable, then, for an engineer or scientist to regard the era of postwar electronics much like many people at Bell Labs did: New devices were waiting to be discovered through the combination of
basic research and the intellectual force of physicists and engineers working together. The world of electronics could move forward through new ideas and the meticulous work of development engineers. “I think that there are vistas ahead that [are] as large or larger than the past,” Mervin Kelly declared in May 1947.
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A more cautious view maintained that the potential new age depended on finding a solution to a cosmic puzzle. Progress, in both technology and business, depended on new materials, and new materials were scattered about the earth in confusion. There were substances that might be useful on their own or combined into compounds—that alone comprised an infinite number. And each of these potential substances could, in turn, be rendered in a laboratory into an almost unimaginable range of purities. One might conceivably find the right material, with the right level of purity, for a new device. Or one might not.

T
HE PURSUIT OF PURITY
at Bell Labs went further than Frank Jewett or Mervin Kelly ever imagined. In 1939, the year Shockley and Brattain had tried and failed to make a solid-state amplifier out of copper oxide, the chemists and metallurgists at the Labs had already begun looking closely at the class of materials called semiconductors. In particular they focused their inquiries on silicon. Already physicists had concluded that many semiconductors exhibited a unique set of behaviors related to their atomic structure. Atoms have a nucleus packed full of protons and neutrons that are surrounded by bands of vibrating electrons. In a good conductor—copper, for instance—the band farthest from the nucleus has only one or two electrons, which means this band is mostly empty. The outermost electrons are often free to bounce around and move to neighboring copper atoms. In a good insulator—glass, for instance—the opposite holds true; the band farthest from the nucleus has seven or eight electrons, which means it is mostly full. The electrons are therefore held in fixed positions. These contrasts translate into differences in how the materials conduct electric current, which might be thought of as a “flow” of electrons through a solid material. In a conductor, electrons move
freely. In an insulator, they don’t. As the Bell Labs researchers would describe it, the electrons in an insulator essentially “act as a rigid cement” to bind together the atoms in the solid.

Semiconductors—as their name implies, neither conductors nor insulators—are a curious case. In their outer band, atoms that comprise these substances have somewhere between three and five electrons, and they seem to exhibit qualities that are different from those of either a conductor or an insulator. Early in the twentieth century, physicists noted that these materials became better electrical conductors as their temperature increased—the opposite of what happened with metals (and good conductors) like copper. In addition, they could in some circumstances produce an electric current when placed under a light—what was known as a photovoltaic effect. Perhaps most compelling, the materials could rectify, meaning they allowed electric signals to pass in one direction only (they could, in other words, convert alternating electric current, AC, to direct current, DC).
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This was a useful property familiar to almost any Bell engineer. The early crystal wireless radios that so many Labs scientists grew up with depended on semiconductor crystals like silicon. Silicon crystals would process the incoming radio signal, transforming a weak AC signal into DC, so it could be heard through a headphone.

Three Bell Labs researchers in particular—Jack Scaff, Henry Theurer, and Russell Ohl—had been working with silicon in the late 1930s, mostly because of its potential for the Labs’ work in radio transmission. Scaff and Theurer would order raw silicon powder from Europe, or (later) from American companies like DuPont, and melt it at extraordinary temperatures in quartz crucibles. When the material cooled they would be left with small ingots that they could test and examine. They soon realized that some of their ingots—they looked like coal-black chunks, with cracks from where the material had cooled too quickly—rectified current in one direction, and some samples rectified current in another direction. At one point, Russell Ohl came across a sample that seemed to do both: The top part of the sample went in one direction and the bottom in the other. That particular piece was intriguing in another
respect. Ohl discovered that when he shone a bright light on it he could generate a surprisingly large electric voltage. Indeed the effect was so striking, and so unexpected, that Ohl was asked to demonstrate it in Mervin Kelly’s office one afternoon. Kelly immediately called in Walter Brattain to take a look, but none of the men had a definitive explanation.
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“In discussing these mysteries Ohl and I decided we needed to characterize them in some way,” the metallurgist Scaff later explained.
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During a phone call, the two men decided to call one type of silicon p-type (for positive conduction) and the other n-type (for negative).

It wasn’t necessarily clear at the start why this was so—or whether it was even important. By the early 1940s, however, Scaff and Ohl were increasingly sure that the two differing types of silicon were the product of almost infinitesimal amounts of different impurities. Atoms within semiconductors bond easily with a number of other elements. Scaff and his colleagues knew that when they cut n-type silicon (atomic number 14) into smaller pieces on a power saw, for instance, they could smell something they were sure was phosphorus (atomic number 15). None of the measurement equipment could pick up the taint, but their noses could.
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Later, the men also determined that p-type silicon often had faint traces of the elements aluminum (13) or boron (5).

This was the beginning of a larger insight. Ultimately the metallurgists Scaff and Ohl agreed that certain elements added to the silicon (such as phosphorus) would add excess electrons to its outer band of electrons; those extra electrons could, in turn, move around and help the silicon conduct current, just as they might in a conductor such as copper. This was n-type silicon. On the other hand, certain other elements added to the silicon (such as boron) created additional empty spaces for electrons in the outer band—these became known as holes. These so-called holes, much like electrons, could also move about and conduct current, like a stream of bubbles moving air through a liquid. This was p-type silicon. For Scaff and Theurer—and, in time, the rest of the solid-state team at Bell Labs—one way to think of these effects was that purity in a semiconductor was necessary. But so was a controlled impurity. Indeed, an almost vanishingly small impurity mixed into silicon, having a net
effect of perhaps one rogue atom of boron or phosphorus inserted among five or ten million atoms of a pure semiconductor like silicon, was what could determine whether, and how well, the semiconductor could conduct a current. One way to think of it—a term that was sometimes used at the Labs—was as a
functional
impurity.