Technique prevents silicon wafers from adhering to susceptor following silicon epitaxial deposition. Annular ring of refractory material goes around wafer during epitaxial deposit. Silicon is deposited on ring, susceptor, and portions of wafer. Ring breaks away from susceptor and wafer and no silicon undergrowth occurs

Bue, J. L.

English

NASA Technical Reports Server

November 1971 Brief 71-10434 
., NASA TECH BRIEF 
Marshall Space Flight Center
	 -4r 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Shielding Method for Polycrystalline and Epitaxy Growths 
is
A new technique prevents silicon wafers from ad-
hering to the susceptor following silicon epitaxial 
deposition. During the epitaxial growth process, 
the silicon forms deposits on the host wafer, on the 
2. 
Wafer	 Graphite Ring 
susceptor, and on the boundary between them. The 
wafers adhere to the continuous layer of deposited 
silicon and have a tendency to crack when the wafer 
and susceptor are cooled. Conventional processing 
used to prevent cracking is expensive and time 
consuming. In addition, silicon undergrowth has 
been a major problem in fabrication processes 
such as those involving dielectric isolation. 
With the new procedure, an annular ring of 
graphite or other refractory material (see fig.) is 
placed around the wafer during the epitaxial de-
posit. Silicon is deposited on the ring, the susceptor
and the exposed portion of the wafer. The ring 
breaks away cleanly from the susceptor and the 
silicon wafer, even when the coating is as thick as 15 
mils, and no silicon undergrowth occurs. 
\ote: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Code A&TS-TU 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B71-10434 
Patent status: 
Title to this invention has been waived under the 
provisions of the National Aeronautics and Space 
Act (42 U.S.C. 2457 (f)), to TRW, Inc. 
Source: J.L. Bue of

TRW, Inc.

under contract to

Marshall Space Flight Center

(MFS-20162) 
Category 04 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Shielding method for polycrystalline and epitaxy growths

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