William Gardner Pfann
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William Gardner Pfann (October 27, 1917 – October 22, 1982) was an
inventor An invention is a unique or novel device, method, composition, idea or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...
and materials scientist with
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...
. Pfann is known for his development of
zone melting Zone melting (or zone refining, or floating-zone method, or floating-zone technique) is a group of similar methods of purifying crystals, in which a narrow region of a crystal is melted, and this molten zone is moved along the crystal. The molte ...
which is essential to the
semiconductor industry The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors and semiconductor devices, such as transistors and integrated circuits. It formed around 1960, once the fabrication of semiconduct ...
. 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 Brooklyn () is a borough of New York City, coextensive with Kings County, in the U.S. state of New York. Kings County is the most populous county in the State of New York, and the second-most densely populated county in the United States, be ...
,
New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
. 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 The Cooper Union for the Advancement of Science and Art (Cooper Union) is a private college at Cooper Square in New York City. Peter Cooper founded the institution in 1859 after learning about the government-supported École Polytechnique in ...
led to a bachelor's degree in
chemical engineering Chemical engineering is an engineering field which deals with the study of operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials int ...
in 1940. Pfann was involved in
William Shockley William Bradford Shockley Jr. (February 13, 1910 – August 12, 1989) was an American physicist and inventor. He was the manager of a research group at Bell Labs that included John Bardeen and Walter Brattain. The three scientists were jointly ...
's efforts with Bell Labs to use
semiconductor A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
s to make devices to replace
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...
s. The early efforts used
germanium Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors s ...
. They made high back-voltage germanium rectifiers in 1945. Pfann devised one of the first
point-contact transistor The point-contact transistor was the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. They worked in a group led by physicis ...
s: "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 Walter Houser Brattain (; February 10, 1902 – October 13, 1987) was an American physicist at Bell Labs who, along with fellow scientists John Bardeen and William Shockley, invented the point-contact transistor in December 1947. They shared the ...
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."


Breakthrough

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.". In 1952, Pfann published the revelatory article "Principles of Zone-Melting" in the ''Transactions of the
American Institute of Mining, Metallurgical, and Petroleum Engineers The American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) is a professional association for mining and metallurgy, with over 145,000 members. It was founded in 1871 by 22 mining engineers in Wilkes-Barre, Pennsylvania, Uni ...
''. 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 model A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used in the natural sciences (such as physics, ...
s of the processes in zone melting. In 1958, Pfann published the first edition of his text ''Zone Melting'' with
John Wiley John Wiley may refer to: *John Wiley & Sons, a publishing company * John A. Wiley (1843–1909), Pennsylvania businessman, National Guard and Civil War soldier *John Cooper Wiley (1893–1967), US foreign service officer and ambassador *John D. Wil ...
. 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 Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ...
'' 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 The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
(U.S.) in 1975. In 1976 the
American Institute of Physics The American Institute of Physics (AIP) promotes science and the profession of physics, publishes physics journals, and produces publications for scientific and engineering societies. The AIP is made up of various member societies. Its corpora ...
awarded him the
James C. McGroddy Prize for New Materials The James C. McGroddy Prize for New Materials is a prize that has been awarded annually by the American Physical Society since 1975, but was only given that name following its endowment by IBM in 1999. Prior to that it was known as the Internation ...
. On his passing some coworkers wrote:
Richard Hamming Richard Wesley Hamming (February 11, 1915 – January 7, 1998) was an American mathematician whose work had many implications for computer engineering and telecommunications. His contributions include the Hamming code (which makes use of a Ha ...
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."
Richard W. Hamming Richard Wesley Hamming (February 11, 1915 – January 7, 1998) was an American mathematician whose work had many implications for computer engineering and telecommunications. His contributions include the Hamming code (which makes use of a Ham ...
(1986
You and Your Research
via
University of Virginia The University of Virginia (UVA) is a Public university#United States, public research university in Charlottesville, Virginia. Founded in 1819 by Thomas Jefferson, the university is ranked among the top academic institutions in the United S ...


Notes


References

* Kenneth A. Jackson, Harry J. Leamy & Richard S. Wagner (February 1983) "William G. Pfann",
Physics Today ''Physics Today'' is the membership magazine of the American Institute of Physics. First published in May 1948, it is issued on a monthly schedule, and is provided to the members of ten physics societies, including the American Physical Society. I ...
36:88. {{DEFAULTSORT:Pfann, William Gardner 20th-century American inventors 1917 births 1982 deaths People from Brooklyn Cooper Union alumni Bell Labs Members of the United States National Academy of Sciences