The effects of rapid thermal oxidation (RTO) on the chemical vapor deposited nitride/oxide layer for thin gate dielectrics were studied. Successful growth of a top oxide of ∼25 A˚ was confirmed using x‐ray photoelectron spectroscopy and no punchthrough of the chemical vapor deposited nitride was observed for a nitride thickness of 60 A˚. Changes in electrical properties after RTO were studied using current‐voltage and charge‐to‐breakdown measurements. Results indicate that the top oxide reduces the leakage current under positive gate bias and increases the leakage current at high fields for negative gate bias. In addition, the charge to breakdown of the layer is increased after RTO.