Intel Corporation

Robert S K Chau

Leopoldo D Yau

William L Hargrove

A novel process for forming a robust, sub-100 &angst; oxide is disclosed. Native oxide growth is tightly controlled by flowing pure nitrogen during wafer push and nitrogen with a small amount of oxygen during temperature ramp and stabilization. First, a dry oxidation is performed in oxygen and 13% trichloroethane. Next, a wet oxidation in pyrogenic steam is performed to produce a total oxide thickness of approximately 80 &angst;. The oxide layer formed is ideally suited for use as a high integrity gate oxide below 100 &angst;. The invention is particularly useful in devices with advanced, recessed field isolation where sharp silicon edges are difficult to oxidize. For an oxide layer of more than 100 &angst;, a composite oxide stack is used which comprises 40-90 &angst; of pad oxide formed using the above novel process, and 60-200 &angst; of deposited oxide.

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Beaverton, OR, United States of America

Robert S K Chau