Diffused junction transistor

Bell Labs developed the first prototype diffused junction bipolar transistors in 1954.

At Bell Labs Calvin Souther Fuller produced basic physical understanding of a means of directly forming the emitter, base, and collector by double diffusion.

The method was summarized in a history of science at Bell:[2] Texas Instruments made the first grown-junction silicon transistors in 1954.

[3] The diffused silicon mesa transistor was developed at Bell Labs in 1955 and made commercially available by Fairchild Semiconductor in 1958.

The planar process used to make these transistors made mass-produced monolithic integrated circuits possible.