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Epitaxial Deposition Process

IP.com Disclosure Number: IPCOM000077434D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bratter, RL: AUTHOR [+2]

Abstract

In thin-film semiconductor devices, failures have been caused by the formation of crystalline imperfections in the deposited epitaxial layer, which serves as pipes allowing enhanced diffusion in localized regions. This frequently causes shorts between the emitter, base. and collector regions of transistors.

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Epitaxial Deposition Process

In thin-film semiconductor devices, failures have been caused by the formation of crystalline imperfections in the deposited epitaxial layer, which serves as pipes allowing enhanced diffusion in localized regions. This frequently causes shorts between the emitter, base. and collector regions of transistors.

In this process, the intersection impurity concentration in the region of the base-collector junction is lowered. This is accomplished by initially depositing a thin capping layer of silicon or other semiconductor material on the top of the subcollector, having a thickness on the order of 0.5 micron. Subsequently, the SiCl stream is shutoff and the temperature of the reactor allowed to drop to approximately to 700 degrees C. The flow of carrier gas through the reactor is continued for approximately 50 min. to flush away any vapor phase dopants. Subsequently, the temperature of the wafer is raised to the initial temperature, and the remaining desired epitaxial layer deposited at a higher resistivity that is a lower dopant concentration.

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