William Gardner Pfann

William Gardner Pfann (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."

Early life

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. He and Walter Brattain developed the process of "forming" these transistors to make them more uniform. This article applied zone melting in two industrial processes: purification of a solvent material (called zone refining), and production of a uniform distribution of a solute in an ingot (called zone leveling). Three appendices described mathematical models of the processes in zone melting.

In 1958, Pfann published the first edition of his text Zone Melting with John Wiley. A second edition appeared in 1966, and in 1978 publisher Robert E. Krieger of Huntington, New York issued the third edition.

In 1962, the journal Science published a short digest of the zone melting method by Pfann. This article concludes by treating the slightly larger topic of temperature gradient zone melting. Pfann describes how and why a drop of gold on a germanium slab moves toward the hottest spot. He says this method was used to "make complex p-n junction shapes for special transistors". He observes the motion of brine on sea ice and proposes the purification of sea water. Further he notes the relation to the physics of geological formations.

Appreciation In 1973 Pfann was the first to receive the Gordon E. Moore Medal for Outstanding Achievement in Solid State Science and Technology. Pfann was elected to the National Academy of Sciences (U.S.) in 1975. In 1976 the American Institute of Physics awarded him the James C. McGroddy Prize for New Materials.

On his passing some coworkers wrote:

Richard Hamming used Pfann to illustrate professional development. At first he noted Pfann "didn't know much mathematics and wasn't really articulate." Then Hamming showed him how to use computers and "his shyness, his awkwardness and his inarticulateness fell away and he became much more productive in many other ways."