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Multicollector Lateral PNP Transistor

IP.com Disclosure Number: IPCOM000083560D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Cullet, R: AUTHOR

Abstract

The figure shows a PNP transistor structure with multicollectors and a common base, made according to bipolar technology.

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Multicollector Lateral PNP Transistor

The figure shows a PNP transistor structure with multicollectors and a common base, made according to bipolar technology.

The PNP transistor includes an emitter E of conductivity type P surrounded by four collectors C1, C2, C3 and C4 of the same type P. The emitter and the four collectors are made in an epitaxial layer of conductivity type N used as the base B of the PNP transistor. The collector pattern permits the obtaining of the maximum gain for the transistor and a minimum injection of minority carriers into the substrate. The rhombus shape of the emitter allows the use of a minimum substrate surface.

A same epitaxial layer can include several PNP transistors. In this case, the base is common to all the transistors. An insulating layer made of silicon dioxide (SiO ) can be provided between adjacent collectors if interactions are to be avoided.

The SiO(2) layer goes deeper in the substrate than the collector diffusion and cancels these interactions.

This PNP transistor structure permits the manufacture of monolithic memories with a high-integration level.

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