Bell Labs' Patents for the Transistor

Any review of historic patents, like this series of posts, has to include arguably the most important invention of the 20th Century: the transistor. The transistor was developed in 1947 by three Bell Labs physicists, John Bardeen, Walter Brattain, and William Shockley, when they were working to find a replacement for the bulky and fragile vacuum tubes in electronic equipment. 

Point-Contact Transistor. Here is the first patent Bell Labs filed, U.S. Patent No. 2,524,035, which names Bardeen and Brattain as inventors and was directed to a point-contact transistor. The specification states that “[t]he principal object of the invention is to amplify or otherwise translate electric signals or variations by use of compact, simple, and rugged apparatus of novel type.”  Claim 1 was directed to the transistor circuit elements including a block of semiconductor material and three electrodes:

A circuit element which comprises a block of semiconductive material of which the body is of one conductivity type and a thin surface layer is of the opposite conductivity type, an emitter electrode making contact with said layer, a collector electrode making contact with said layer disposed to collect current spreading from said emitter electrode, and a base electrode making contact with the body of the block.

Junction Transistor. In 1948, Bell Labs filed for U.S. Patent No. 2,502,488, which names Shockley as the sole inventor and was directed to a junction transistor. The three inventors were jointly awarded the 1956 Nobel Prize in Physics for their research and discoveries.

Invention Story with Drama. The story of the transistor's development and the human drama among its three inventors (the ensuing publicity and jockeying for credit quickly drove the team apart) is a fascinating one and is the subject of several books. I mentioned The Idea Factory about Bell Labs in a prior post, and Crystal Fire by Michael Riordan and Lillian Hoddeson is on my to-read list.

Exemplifying the Scientific Method. What stands out from these patents is the scientific endeavor involved. Compared with Edison's light bulb patent in my earlier post, the Bardeen/Brattain patent is long, spanning nearly 16 columns of written description. It includes both an explanation of the electrical and chemical theory behind the invention (Bardeen was a theoretical physicist) and a detailed recitation of their experiments (Brattain was an experimental physicist). The patents make clear that it was a true scientific method – performing experiments to test hypotheses – that led to this revolutionary invention.