page_title: Invention of the integrated circuit
section_title: Planar process
hierarchical_section_title: Invention of the integrated circuit / Prerequisites / Silicon technology / Planar process
caption_attribution_description: Сравнение планарного транзистора по Эрни (первое поколение, справа) с меза-транзистором (слева)
context_page_description: The integrated circuit chip was invented during 1958–1959. The idea of integrating electronic circuits into a single device was born when the German physicist and engineer Werner Jacobi developed and patented the first known integrated transistor amplifier in 1949 and the British radio engineer Geoffrey Dummer proposed to integrate a variety of standard electronic components in a monolithic semiconductor crystal in 1952. A year later, Harwick Johnson filed a patent for a prototype IC. Between 1953 and 1957, Sidney Darlington and Yasuro Tarui proposed similar chip designs where several transistors could share a common active area, but there was no electrical isolation to separate them from each other.
  These ideas could not be implemented by the industry, until a breakthrough came in late 1958. Three people from three U.S. companies solved three fundamental problems that hindered the production of integrated circuits. Jack Kilby of Texas Instruments patented the principle of integration, created the first prototype ICs and commercialized them. Kilby's invention was a hybrid integrated circuit, rather than a monolithic integrated circuit chip.
context_section_description: Jean Hoerni attended the same 1958 Electrochemical Society meeting, and was intrigued by Mohamed Atalla's presentation of the surface passivation process. Hoerni came up with the "planar idea" one morning while thinking about Atalla's device. Taking advantage of silicon dioxide's passivating effect on the silicon surface, Hoerni proposed to make transistors that were protected by a layer of silicon dioxide. This led to the first successful product implementation of the Atalla silicon transistor passivation technique by thermal oxide.
  Jean Hoerni first proposed a planar technology of bipolar transistors. In this process, all the p-n junctions were covered by a protective layer, which should significantly improve reliability. However, at the time, this proposal was considered technically impossible. The formation of the emitter of an n-p-n transistor required diffusion of phosphorus, and the work of Frosch suggested that SiO₂ does not block such diffusion. In March 1959, Chih-Tang Sah, a former colleague of Hoerni, pointed Hoerni and Noyce to an error in the conclusions of Frosch. Frosch used a thin oxide layer, whereas the experiments of 1957–1958 showed that a thick layer of oxide can stop the phosphorus diffusion.
  Armed with the above knowledge, by March 12, 1959, Hoerni made the first prototype of a planar transistor, and on May 1, 1959 filed a patent application for the invention of the planar process. In April 1960, Fairchild launched the planar transistor 2N1613, and by October 1960 completely abandoned the mesa transistor technology. By the mid-1960s, the planar process has become the main technology of producing transistors and monolithic integrated circuits.
caption: Comparison of the mesa (left) and planar (Hoerni, right) technologies. Dimensions are shown schematically.
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