The
grown-junction transistor was the first type of bipolar
junction transistor made. It was invented by
William Shockley at
Bell Labs on June 23, 1948 (patent filed June 26, 1948), six months after the first bipolar
point-contact transistor. The first
germanium prototypes were made in 1949. Bell Labs announced Shockley’s grown-junction transistor on July 4, 1951.