Diffused junction transistor: Difference between revisions

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A '''diffused junction transistor''' is a [[transistor]] formed by diffusing [[dopant]]s into a [[semiconductor]] [[Wafer (electronics)|substrate]]. The diffusion process was developed later than the [[Alloy-junction transistor|alloy -junction]] and [[Grown-junction transistor|grown junction]] processes for making bipolar junction transistors (BJTs).

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

==Diffused-base transistor==

The earliest diffused junction 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==

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}}, p.&nbsp;11.</ref>

The diffused silicon '''mesa transistor''' was developed at [[Bell Labs]] in 1955 and made commercially available by [[Fairchild Semiconductor]] in 1958.<ref>{{Harvnb|Lécuyer|Brock|2010|pp=10–22}}</ref>

These transistors were the first to have both diffused bases and diffused emitters. Unfortunately, like all earlier transistors, the edge of the collector–base junction was exposed, making it sensitive to leakage through surface contamination, thus requiring [[hermetic seal]]s or [[Passivation (chemistry)|passivation]] to prevent degradation of the transistor's characteristics over time.<ref>{{cite web |url=https://spectrum.ieee.org/semiconductors/design/the-silicon-dioxide-solution |archive-url=https://web.archive.org/web/20110215031520/http://spectrum.ieee.org/semiconductors/design/the-silicon-dioxide-solution |url-status=dead |archive-date=February 15, 2011 |title=The Silicon Dioxide Solution: How physicist Jean Hoerni built the bridge from the transistor to the integrated circuit|author1-link=Michael Riordan (physicist) |first=Michael |last=Riordan |work=IEEE Spectrum |date=December 2007 |accessdateaccess-date=November 28, 2012 |publisher=IEEE}}</ref>

==Planar transistor==