W. G. Pfann
October 25, 1917 - October 26, 1982
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Scientific Discipline: Applied Physical Sciences Membership Type:
Member
(elected 1974)
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Materials scientist W. G. Pfann was best known for his invention of the zone-refining process, which enabled the efficient manufacturing of transistors. Pfann earned more than sixty-five patents for zone-melting, semi-conductive devices, and crystal growth techniques. The purities of industrial samples of over one-third of the elements on the periodic table have been greatly increased because of his process. While working at Bell Telephone Laboratories, he began developing silicon crystal detectors for radar receivers and studied the purification and crystal growth processes of silicon. He then studied the fundamental materials aspect of electrical contact erosion, which led to his discovery of a method to eliminate bridge erosion due to the passing voltages. It was in 1951 that Pfann made his crucial invention of the zone-refining process. In this process, purification by repeated crystallization was efficiently completed by passing several molten zones in tandem through a solid material. This technique made it possible to maintain desired impurities and eliminate the others so that the end result was a semiconductor of unrivaled purity.
Pfann attended the Cooper Union School of Engineering and earned his B.Ch.E. degree in 1940. He was working at Bell Telephone laboratories during his time at college (he started working there in 1936) and stayed there until his retirement. He was the recipient of several different awards for his zone refining process invention, the most notable of which were the Clamer Medal from the Franklin Institute in 1957, the Mathewson Gold Medal from AIME in 1958, and the Professional Progress Award from the American Institute of Chemical Engineers in 1960. Although the Nobel Prize for transistor technology went to other scientists, Pfann was the unsung hero of the zone-refining process that brought semiconductor technology to the world.
