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John Bardeen

  


   


May 23, 1908 in Madison, Wisconsin - Boston 30.January.1991

1947 Transistor
       
   
       

Co inventor with Brattain and Shockley of transistors 1947  




The road that led Shockley, Bardeen and Brattain the invention of the transistor. (1)


   

 Brattain tried to achieve a metal-insulator-semiconductor that would allow the amplification of a signal effectively. The idea was simple: applying a positive voltage to electrode metal should have been able to attract electrons in the semiconductor, taking the external circuit. The strength of the semiconductor would fall due and therefore increase electricity: it would be able to obtain amplification of the signal applied to electrode metal. The device non Did not work. The device did not work. Bardeen said the explanation of failure: the electrons were actually drawn in germanium and Thickened the surface where they remained trapped but because of the poor quality of the surface itself, ruined by cutting and processing.  The idea, however, was completely valid and today is the basis of a whole family of devices: 'effect transistor field.

Experimentation continued, an experimental error led to the discovery of amplification tried, though not by the structure required. During the cleaning of germanium crystal was removed the thin layer of insulation and contact metal was then carried out directly on the semiconductor, and this gave rise to a new result that was carefully considered and not just dismissed, as the result of an error.  Were applied to the two metal contacts germanium pointed very close: the intensity of the current circulating between the two points and third mass contact increased to the point where a voltage was applied. Also, a modulated signal sent to one of two points appeared to amplified: thus obtained had the effect of amplification of electrical signals modulated long sought. 





note:1)  extract    William Shockley, John Bardeen et Walter Brattain- http://www2.mater.unimib.it/cdl/nobel/shockley.html