We present here a rapid thermal processing (RTP) technique that uses in situ generated HCl for growing chlorinated oxides. A gas mixture consisting of oxygen and a benign organic precursor was made to flow over the heated wafer surface where the gases reacted to generate the HCl at the wafer site. This method is a considerable improvement over all of the existing chlorination techniques because it provides much higher safety, lower contamination potential, greater process simplicity, and is produced at a lower cost. Our data on thin oxides shows that in situ chlorination provides benefits that are similar to those of conventional chlorination methods, namely, oxides with lower interface states and higher growth rates than those of standard dry oxides. Secondary ion mass spectrometry plots show that no carbon is introduced in the chlorinated oxide even though it is grown directly in the presence of an organic precursor.w Other electrical data demonstrates no degradation in leakage current and charge trapping through chlorination. (C) 2000 The Electrochemical Society. S0013-4651 (00)04-005-2. All rights reserved.