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Silicon Substrate with Large Defect Free Zone for High Device Yield

IP.com Disclosure Number: IPCOM000045070D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ahlgren, DC: AUTHOR [+2]

Abstract

In this article, a process is described to create a large defect-free zone at the surface of semiconductor substrates. At the same time oxygen precipitation defects are maintained in the middle of the wafer. The process combines out-diffusion of oxygen during a high temperature anneal in the presence of HC1 with the elimination of defect nuclei.

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Silicon Substrate with Large Defect Free Zone for High Device Yield

In this article, a process is described to create a large defect-free zone at the surface of semiconductor substrates. At the same time oxygen precipitation defects are maintained in the middle of the wafer. The process combines out- diffusion of oxygen during a high temperature anneal in the presence of HC1 with the elimination of defect nuclei.

The process consists of annealing silicon wafers at a sufficiently high temperature greater than 1150 degrees C in dry oxygen in the presence of hydrogen chloride (HC1). The volume of the HC1 can be varied from 0.5 to 15 percent of the total atmosphere. An inert gas and HC1 mixture can also be used during the annealing step.

An oxygen ambient is preferred, however, to prevent etching. The use of a 1200 degrees C anneal for two hours provides an oxide thickness of 3700 angstroms along with the production of a very wide defect-free zone. During subsequent low temperature operations, oxygen precipitation takes place in the middle of the wafer. A defect-free zone of approximately 50 microns is provided.

A second anneal in an oxygen-HC1 ambient can be used to provide a wider defect-free zone. This second oxidation will typically be at 1,100 degrees C for 2-4 hours.

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