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Gettering Process for Wafer Defect Reduction

IP.com Disclosure Number: IPCOM000078069D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gates, HR: AUTHOR

Abstract

Precipitates of metallic materials such as copper, nickel and iron have been known to be the probable cause of excess junction and surface leakage in advance field-effect transistors or charge-coupled devices, which require very low levels of junction or surface leakage. The excess leakage is a result of high-defect density.

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Gettering Process for Wafer Defect Reduction

Precipitates of metallic materials such as copper, nickel and iron have been known to be the probable cause of excess junction and surface leakage in advance field-effect transistors or charge-coupled devices, which require very low levels of junction or surface leakage. The excess leakage is a result of high- defect density.

The known method for gettering of such metallic precipitates have involved the use of gettering diffusion such as a standard isolation diffusion, or the use of phosphosilicate glass or boron glass on the wafer surface. Of course, both of these known approaches are carried out subsequent to the initial oxidation of the wafer surface.

The present method recognizes the desirability of accomplishing the gettering of such metallic impurities out of the wafer, prior to any initial oxidation. In this manner, metallic materials are prevented from forming at the interface of the silicon substrate and the oxide.

The method may be accomplished by initially processing the wafer substrate at an elevated temperature and intimate contact with a gettering medium, such as phosphorus or boron glass. The time and temperature of such contact will vary in accordance with conventional knowledge for the accomplishment of the most complete gettering. The gettering layer is then either removed by etching, or alternatively it may be covered with an epitaxial layer in a case where the epitaxial layer is utilized in device f...