In 1948, the point-contact transistor was independently invented by two German physicists working in Paris. (1947 Milestone) Herbert Mataré and Heinrich Welker had been deeply involved in the German radar effort during World War II. Mataré developed crystal rectifiers from silicon and germanium at the Telefunken laboratories in Berlin and Silesia, while Welker worked on purifying germanium in Munich. After the war ended, they were hired by the Compagnie des Freins et Signaux, a Westinghouse subsidiary, to develop and manufacture solid-state rectifiers from these materials.
In 1947 Mataré began researching an odd phenomenon called "interference" that he had witnessed in germanium rectifiers during the War. If two point contacts were sufficiently closely spaced, within 100 micrometers of each other, the potential on one of them could influence the current flowing through the other - similar to what Bardeen and Brattain were seeing in germanium. Early the next year Mataré achieved sporadic amplification of electrical signals. By June 1948 he obtained consistent, reproducible results using higher-purity samples of germanium produced by Welker. But a month later, they learned the surprising news that Bell Labs had just invented a similar semiconductor amplifier. The company rushed to get the device, dubbed the "transistron" to distinguish it from the transistor, into production.
By mid-1949, thousands of them were being manufactured for use as amplifiers in the French telephone system. But ungainly point-contact devices were soon superseded by the junction transistor.(1948 Milestone) Mataré returned to Germany and in 1952 co-founded Intermetall to manufacture diodes and transistors. Welker joined Siemens, eventually becoming its research director.
Mataré Herbert F. and Welker, Heinrich. "Crystal Device for Controlling Electric Currents by Means of a Solid Semiconductor," U. S. Patent 2,673,948 (Filed August 11, 1949. Issued March 30, 1954).
Matare, H.F. "The Three-Electrode Crystal (Transistor)," Das Elektron in Wissenschaft und Technologie Vol. 3 Issue 7 (1949) p. 255.
Markoff, John. "Herbert F. Mataré: An Inventor of the Transistor Has His Moment," New York Times (February 24, 2003).
Van Dormael, Armand. "The 'French' Transistor," Proceedings of the 2004 IEEE Conference on the History of Electronics, Bletchley Park, England (June 2004).
Riordan, Michael. "How Europe Missed the Transistor," IEEE Spectrum (November 2005), pp. 46-51.