![]() Moore, Fairchild’s scientists and engineers extended this revolutionary technique to the manufacture of integrated circuits. The company was soon making and selling planar silicon transistors, largely for military applications. At Fairchild, physicist Jean Hoerni developed the planar manufacturing process, whereby the various semiconductor layers and their sensitive interfaces are embedded beneath a protective silicon dioxide outer layer. Texas Instruments, Fairchild Semiconductor Corporation, and other companies took the lead in applying these diffusion technologies to the large-scale manufacture of transistors. This layer offered transistor producers a promising way to protect the silicon underneath from further impurities once the diffusion process was finished and the desired electrical properties had been established. ![]() ![]() These diffused-base transistors could be used in receivers and transmitters for FM radio and television, which operate at such high frequencies.Īnother important breakthrough occurred at Bell Labs in 1955, when Carl Frosch and Link Derick developed a means of producing a glassy silicon dioxide outer layer on the silicon surface during the diffusion process. For the first time, diodes and transistors produced by these diffusion implantation processes functioned at frequencies above 100 megahertz (100 million cycles per second). Inside a diffusion furnace the impurity atoms penetrate more readily into the silicon or germanium surface their penetration depth is controlled by varying the density, temperature, and pressure of the gas as well as the processing time. In the mid-1950s Bell Labs focused its transistor-development efforts around new diffusion technologies, in which very narrow semiconductor layers-with thicknesses measured in microns, or millionths of a metre-are prepared by diffusing impurity atoms into the semiconductor surface from a hot gas. In 1954 Texas Instruments produced the first commercially available silicon junction transistors and quickly dominated this new market-especially for military applications, in which their high cost was of little concern. Silicon transistors have far less leakage. Germanium transistors make leaky switches substantial leakage currents can flow when these devices are supposedly in their off state. Because of its higher melting temperature and greater reactivity, silicon was much more difficult to work with than germanium, but it offered major prospects for better performance, especially in switching applications. May transistors bundled together form an integrated circuit.ĭuring the 1950s, meanwhile, scientists and engineers at Bell Labs and Texas Instruments were developing advanced technologies needed to produce silicon transistors. The input signal can be changed by varying its voltage. This is typically done with a separate input signal that controls the flow of electricity through the transistor. It is used to amplify and divert electrical currents in electronic devices. A transistor is a device with an intermediate or variable electrical conductivity.
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