The Innovators: How a Group of Inventors, Hackers, Geniuses, and Geeks Created the Digital Revolutio - Isaacson Walter. Страница 47

When his boss, Willis Adcock, returned from vacation he was not fully persuaded that this would be practical. There were other things for the lab to do that seemed more pressing. But he made Kilby a deal: if he could make a working capacitor and resistor, Adcock would authorize an effort to do a complete circuit on a single chip.

All went as planned, and in September 1958 Kilby prepared a demonstration that was similar in drama to the one Bardeen and Brattain had done for their superiors at Bell Labs eleven years earlier. On a silicon chip the size of a short toothpick, Kilby assembled the components that would, in theory, make an oscillator. Under the gaze of a group of executives, including the chairman of the company, a nervous Kilby hooked up the tiny chip to an oscilloscope. He looked at Adcock, who shrugged as if to say, Here goes nothing. When he pushed a button, the line on the oscilloscope screen undulated in waves, just as it should. “Everybody broke into broad smiles,” Reid reported. “A new era in electronics had begun.”⁵

It was not the most elegant device. In the models that Kilby built that fall of 1958, there were a lot of tiny gold wires connecting some of the components within the chip. It looked like expensive cobwebs sticking out of a silicon twig. Not only was it ugly; it was also impractical. There would be no way to manufacture it in large quantities. Nevertheless, it was the first microchip.

In March 1959, a few weeks after filing for a patent, Texas Instruments announced its new invention, which it dubbed a “solid circuit.” It also put a few prototypes on display, with much fanfare, at the Institute of Radio Engineers annual conference in New York City. The company’s president declared that the invention would be the most important one since the transistor. It seemed like hyperbole, but it was an understatement.

The Texas Instruments announcement struck like a thunderbolt at Fairchild. Noyce, who had jotted down his own version of the concept two months earlier, was disappointed at being scooped and fearful of the competitive advantage it might give Texas Instruments.

NOYCE’S VERSION

There are often different paths to the same innovation. Noyce and his Fairchild colleagues had been pursuing the possibility of a microchip from another direction. It began when they found themselves hit with a messy problem: their transistors were not working very well. Too many of them failed. A tiny piece of dust or even exposure to some gases could cause them to fizzle. So, too, might a sharp tap or bump.

Jean Hoerni, a Fairchild physicist who was one of the traitorous eight, came up with an ingenious fix. On the surface of a silicon transistor, he would place a thin layer of silicon oxide, like icing atop a layer cake, that would protect the silicon below. “The building up of an oxide layer . . . on the surface of the transistor,” he wrote in his notebook, “will protect the otherwise exposed junctions from contamination.”⁶

The method was dubbed “the planar process” because of the flat plane of oxide that sat on top of the silicon. In January 1959 (after Kilby had come up with his ideas but before they were patented or announced), Hoerni had another “epiphany” while showering one morning: tiny windows could be engraved in this protective oxide layer to allow impurities to be diffused at precise spots in order to create the desired semiconductor properties. Noyce loved this idea of “building a transistor inside a cocoon,” and he compared it to “setting up your jungle operating room—you put the patient inside a plastic bag and you operate inside of that, and you don’t have all the flies of the jungle sitting on the wound.”⁷

The role of patent lawyers is to protect good ideas, but sometimes they also stimulate them. The planar process became an example of this. Noyce called in John Ralls, Fairchild’s patent lawyer, to prepare an application. So Ralls began grilling Hoerni, Noyce, and their coworkers: What practical things could be done with this planar process? Ralls was probing to obtain the widest range of possible uses to put in the patent application. Recalled Noyce, “The challenge from Ralls was, ‘What else can we do with these ideas in terms of patent protection?’?”⁸

At the time, Hoerni’s idea was merely designed to build a reliable transistor. It had not yet occurred to them that the planar process with its tiny windows could be used to permit many types of transistors and other components to be etched onto a single piece of silicon. But Ralls’s persistent questioning got Noyce thinking, and he spent time that January batting around ideas with Moore, scribbling them on a blackboard and jotting them into his notebook.

Noyce’s first realization was that the planar process could eliminate the tiny wires that stuck out of each layer of the transistor. In their place, little copper lines could be printed on top of the oxide layer. That would make manufacturing the transistors faster and more reliable. This led to Noyce’s next insight: if you used these printed copper lines to connect the regions of a transistor, you could also use them to connect two or more transistors that were on the same piece of silicon. The planar process with its window technique would allow you to diffuse impurities so that multiple transistors could be placed on the same silicon chip, and the printed copper wires could connect them into a circuit. He walked into Moore’s office and drew the idea on the blackboard for him.

Noyce was a talkative bundle of energy and Moore was a taciturn yet insightful sounding board, and they played off each other well. The next leap was easy: the same chip could also contain various components, such as resistors and capacitors. Noyce scribbled on Moore’s blackboard to show how a small section of pure silicon could serve as a resistor, and a few days later he sketched out how to make a silicon capacitor. The little metal lines printed on the oxide surface could integrate all of these components into a circuit. “I don’t remember any time when a light bulb went off and the whole thing was there,” conceded Noyce. “It was more like, every day, you would say, ‘Well, if I could do this, then maybe I could do that, and that would let me do this,’ and eventually you had the concept.”⁹ After this flurry of activity he wrote an entry in his notebook, in January 1959: “It would be desirable to make multiple devices on a single piece of silicon.”¹⁰

Noyce had come up with the concept of a microchip independently of (and a few months later than) Kilby, and they had gotten there in different ways. Kilby was trying to solve the problem of how to overcome the tyranny of numbers by creating circuits with many components that did not have to be soldered together. Noyce was mainly motivated by trying to figure out all the neat tricks that could come from Hoerni’s planar process. There was one other, more practical difference: Noyce’s version didn’t have a messy spider’s nest of wires protruding from it.

PROTECTING DISCOVERIES

Patents present an inevitable source of tension in the history of invention, especially so in the digital age. Innovations tend to proceed through collaboration and building on the work of others, so it is difficult to ascribe with precision the ownership of ideas or intellectual property rights. Occasionally this is made gloriously irrelevant when a group of innovators agrees to engage in an open-source process that allows the fruits of their creativity to be in the public domain. More often, however, an innovator wants credit. Sometimes this is for ego reasons, as was the case when Shockley maneuvered to be listed on the patents for the transistor. At other times it is for financial reasons, especially when it involves companies such as Fairchild and Texas Instruments that need to reward investors in order to have the working capital necessary to keep inventing things.