William Gardner Pfann

William Gardner Pfann (commonly called Bill; October 27, 1917 – October 22, 1982) was an inventor and materials scientist with Bell Labs. Pfann is known for his development of zone melting which is essential to the semiconductor industry. As stated in an official history of Bell Labs, "Timely invention of zone refining by W.G.Pfann ... was a major contribution that helped bring the impurities in germanium and silicon under control."

Pfann was born in Brooklyn, New York City. Showing unusual facility with materials, in 1935, when he was only eighteen years of age, he started with the Chemical Research Department of Bell Labs. He had no college degree at that time, but attending night school at Cooper Union led to a bachelor's degree in chemical engineering in 1940.

Pfann was involved in William Shockley's efforts with Bell Labs to use semiconductors to make devices to replace vacuum tubes. The early efforts used germanium. They made high back-voltage germanium rectifiers in 1945. Pfann devised one of the first point-contact transistors: "Specifically, W.G. Pfann had modified the Western Electric 1N26 shielded point-contact (silicon) diode to include two spring-loaded cat whisker point contacts, making a three-electrode configuration with good electrical amplifying properties. This configuration became known at the Type A transistor." He and Walter Brattain developed the process of "forming" these transistors to make them more uniform. Pfann also invented a method of bonding fine gold wires to germanium that made the device functional. "The quiet, unassuming man grew steadily in everyone's esteem as he made one valuable contribution after another to the semiconductor research effort."

The zone melting process that Pfann is known for revolutionized engineering possibilities: "The purity that can be attained by zone refining was absolutely unprecedented in the history of materials processing. Impurity levels of a few parts per million had previously been considered excellent; Pfann's technique improved on this by factors of over 1,000.".

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