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Browse Prior Art Database

Forming PN Junctions during Vapor Growth

IP.com Disclosure Number: IPCOM000094762D
Original Publication Date: 1965-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lyons, VJ: AUTHOR

Abstract

This method automatically forms PN junctions in an epitaxial layer grown on a semiconductor body. A silicon substrate is doped with donor elements (antimony 5x10/18//cc) having a specific diffusion coefficient and acceptor elements (boron 2x10/18//cc) having a different diffusion coefficient. An epitaxial layer is grown on the silicon substrate and both dopants diffuse into the layer during its growth.

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Forming PN Junctions during Vapor Growth

This method automatically forms PN junctions in an epitaxial layer grown on a semiconductor body. A silicon substrate is doped with donor elements (antimony 5x10/18//cc) having a specific diffusion coefficient and acceptor elements (boron 2x10/18//cc) having a different diffusion coefficient. An epitaxial layer is grown on the silicon substrate and both dopants diffuse into the layer during its growth.

Since the dopant (boron) with the highest diffusion coefficient has a lower concentration in the substrate than the other dopant (antimony), the epitaxial region adjacent the substrate has the conductivity of the dopant with the highest carrier concentration. The faster diffusion dopant controls the conductivity of a region of the epitaxial layer spaced from the substrate.

An NPN transistor arrangement on an N+ substrate is made in this manner. In one example, the P-region is approximately .6 micron wide and begins at a distance of about .5 micron from the substrate. Variations in temperature, time, impurity concentrations, etc., provide a number of different transistor arrangements.

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