Siemens & Halske Transistor Innovation

The Siemens brothers were industrialists from the mid 19th century, Siemens & Halske being one arm of several. At some point post WWII, the remaining entities merged into Siemens AG. 

The patent shown in the image was filed in Germany in 1956 and in the US one year later. At the time the dominant transistor manufacturing technology was alloy junction. The method described in the patent was an early adoption of diffusion for creating the process layers with masking and etching, similar to the mesa transistor structure which emerged around the same time in the US.

Depositing metal instead of attaching gold wires, embedding the diffused layers and a protective layer on the surface would be the basis of the planar process subsequently invented by Fairchild. 

Siemens first established transistor manufacturing in their electron tube facility in Munich in 1952.

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