Jean Hoerni is the Swiss born physicist who developed the planar process while working at Fairchild Semiconductor. This led to the invention of the integrated circuit. Hoerni was one of the traitorous eight who left Shockley Semiconductor in 1957 to help form Fairchild. For over 40 years the planar process has been the primary method of making transistors.

Hoerni came to the United States in 1952 with two doctorates in physics, one from Cambridge University and the other from the University of Geneva. He was looking for a career in research and ended up at Caltech. He wasn't one to brag about his genius. His family said he wasn't the least bit pretentious and even asked them not to ask about his studies. His strength was in theory and pretentious or not his genius did not go unnoticed. William Shockley approached him and several other genius types to work for him in the new company he was starting up, Shockley Semiconductor.

After about a year, Hoerni and seven others, including Gordon Moore and Robert Noyce decided to leave Shockley. They were tired of his oppressive management and had differing views on which direction they should be going. They stated Fairchild Semiconductor and came to be known as the Shockley Eight or as Shockley called them, the "traitorous eight". They wanted to beat Shockley at developing the first integrated circuit, as well as turn a profit.

The main problem facing the industry at the time was the tyranny of numbers which was a limit to the number of circuits that could be squeezed into a device. Double diffusion transistors, the tiny three-layer chips of P-N-P silicon were very prone to contamination since the components and connections were exposed. A little piece of dust or an errant electric charge could influence transistor behavior. In 1958 Hoerni had a solution. The idea came to him while he was taking his morning shower. He suggested putting a layer of silicon oxide on top of the chip. This went against the standard belief of the day that the silicon itself was a contaminent. They discovered that the oxide held firm to the silicon and protected the devise from contaminants. They called it the planar process because the finished product had a flat plane on top.

It wasn't long before Robert Noyce saw further applications using the planar process. He developed the first integrated circuit that had no exposed wires. The transistors and all of their connections were "painted" onto the silicon surface. Then the top layer of silicon was added using oxidation and heat diffusion to form a smooth insulating surface. Everything was inside the silicon and protected. Soon Fairchild was mass producing chips and went on to become one of the most successful companies in Silicon Valley durin the 1960s.

Hoerni left Faichild before their peak and started several other companies over the years. One of them was Intersil Inc. which dealt mainly with the development of analog and mixed-signal integrated circuits. He was an ardent mountain climber who scaled many of the world's peaks as well as a partial assent of Mount Everest. He was just at home talking to mountain sherpas as he was talking to reknowned physicists. He donated money to help build a school in a remote part of Pakistan and set up an endowment to serve the people of the area after he was gone. He died in February 1997 at the age of 72.

Sources:
T. R. Reid. The Chip. New York: Simon and Schuster, 1984
Forrest M. Mims, III.Siliconnections. New York: McGraw-Hill Book Co., 1986
Deborah Claymon. Jean Hoerni, 1924-1997. Red Herring (http://www.redherring.com/mag/issue42/obituary.html)

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