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1: 108 concentration approx teaspoon / swimming pool
1: 108 concentration approx teaspoon / swimming pool
1940 PN junction diode discovered Russel Ohl, Bell labs
Investigating Cat’s whisker detectors
Noticed conduction through crystal of germanium he’d grown changed on exposure to light. Crack in crystal due to differing impurities in 2 halves of crystal during growth.
Walter Brittain deduced ‘junction’ at crack – semiconduction
Within 1 year germanium diodes for radar sets
Junction needs to be in single crystal, diffuse in dopants
23 December 1947  Birth of transistor age
Bell Labs
Razor cut in gold wire round plastic wedge
wedge pressed against germanium crystal
Amplification of current
Nobel prize in 1956 for Bardeen, Brittain & Shockley
Shockley looking through microscope.
Bardeen on left
Brittain on right
Shockley semiconductor working on 4-layer diode structure
Paranoid management style, forced staff to take polygraph test after secretary injured herself – last straw.
Gordon E. Moore, C. Sheldon Roberts, Eugene Kleiner, Robert N. Noyce, Victor H. Grinich, Julius Blank, Jean A. Hoerni and Jay T. Last
backing from Fairchild Camera & Instrument Corp
1963 Shockley leave electronics industry for chair at Stanford
Formulates ‘dysgenics’ , proposes sterilisation for anyone with IQ<100
Early experiments used germanium
Rare element.
Initial problems refining silicon overcome
Planar process developed by