Doping (Semiconductors)

In semiconductor production, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical properties. The doped material is referred to as extrinsic semiconductors. A semiconductor doped to such high levels that it acts more like a conductor than a semiconductor is referred to as a degenerate semiconductor.

In the context of phosphors and scintillators, doping is better known as activation. Doping is also used to control the color in some pigments.

The effects of semiconductor doping were long known empirically in such devices as crystal radio detectors and selenium rectifiers. For instance, in 1885 Shelford Bidwell, and in 1930 the German scientist Bernhard Gudden, each independently reported that the properties of semiconductors were due to the impurities contained within them. The doping process was formally first developed by John Robert Woodyard working at Sperry Gyroscope Company during World War II, with a US Patent issued in 1950. The demands of his work on radar denied Woodyard the opportunity to pursue research on semiconductor doping.

Similar work was performed at Bell Labs by Gordon K. Teal and Morgan Sparks, with a US Patent issued in 1953.

Woodyard's prior patent proved the grounds of extensive litigation by Sperry Rand .

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