Browse Prior Art Database

Insuring Consistent Doping Levels of Epitaxial Layers Grown on Batches of Wafers

IP.com Disclosure Number: IPCOM000079044D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Bratter, RL: AUTHOR [+2]

Abstract

U. S. Patent 3,424,629 describes an apparatus and method for epitaxial growth on a batch of wafers in apparatus known as a "Barrel Reactor", wherein the wafers are mounted in a plurality of concentric rings about a cylinder mounted on a longitudinal rotating axis.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Insuring Consistent Doping Levels of Epitaxial Layers Grown on Batches of Wafers

U. S. Patent 3,424,629 describes an apparatus and method for epitaxial growth on a batch of wafers in apparatus known as a "Barrel Reactor", wherein the wafers are mounted in a plurality of concentric rings about a cylinder mounted on a longitudinal rotating axis.

In accordance with conventional procedure for the deposition of epitaxial layers in such barrel reactors or similar structures, the vaporized feed is usually longitudinal, i.e., it enters the system from either the top or the bottom and travels longitudinally, respectively leaving from the opposite port. With such a longitudinal flow, it has been found that there may be a tendency, particularly with respect to epitaxial deposition on highly doped silicon substrates, for autodoping to take place wherein impurities from the rings of wafers initially passed by the feed stream, enter the feed stream and are, thereby, deposited on subsequently traversed wafers to produce higher doping levels in such subsequently traversed wafers. As a result, there may be inconsistencies in the doping levels of the epitaxial layers of the various wafers in the batch.

One solution for this problem, is to intermittently and periodically reverse the flow of the longitudinal feed stream to the opposite direction land and then back to the original direction. This would compensate for the autodoping effects.

Another solution is a system as shown in th...