Diffused junction transistor: Difference between revisions

Revision as of 21:17, 3 January 2016

Revision as of 17:18, 10 January 2016

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{{refimprove|date=February 2011}}

A '''diffusion transistor''' is anya [[bipolar junction transistor]] (BJT) formed by diffusing [[dopant]]s into a [[semiconductor]] [[Wafer (electronics)|substrate]]. Diffusion transistors include some types of both [[bipolar junction transistor]]s and [[field-effect transistor]]s. The diffusion process was developed later than the [[Alloy-junction transistor|alloy junction]] and [[Grown-junction transistor|grown junction]] processes for making BJTs.

[[Bell Labs]] developed the first prototype diffusion transistors in 1954.<ref>[http://semiconductormuseum.com/PhotoGallery/PhotoGallery_Prototype_DiffusedBase.htm Transistor Museum, Historic Transistor Photo Gallery, '''Bell Labs Prototype Diffused Base Triode''']</ref>

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==Diffused-base transistor==

The earliest diffusion transistors were '''diffused-base transistors'''. These transistors still had alloy emitters and sometimes alloy collectors like the earlier alloy-junction transistors. Only the base was diffused into the substrate. Sometimes the substrate formed the collector, but in transistors like [[Philco]]'s [[micro-alloy diffused transistor]]s the substrate was the bulk of the base.

==Double diffusion==

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 1983 in a history of science at Bell:<ref>Millman (1983) p 426</ref>