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The effects of postdeposition anneal of chemical vapor deposited silicon nitride are studied. The Si/sub 3/N/sub 4/ films were in situ annealed in either H/sub 2/(2%)/O/sub 2/ at 950/spl deg/C or N/sub 2/O at 950/spl deg/C in a rapid thermal oxidation system. It is found that an interfacial oxide was grown at the Si/sub 3/N/sub 4//Si interface by both postdeposition anneal conditions. This was confirmed by thickness measurement and X-ray photoelectronic spectroscopy (XPS) analysis. The devices with H/sub 2/(2%)/O/sub 2/ anneal exhibit a lower gate leakage current and improved reliability compared to that of N/sub 2/O anneal. This improvement is attributed to a greater efficiency of generating atomic oxygen in the presence of a small amount of hydrogen, leading to the elimination of structural defects in the as-deposited Si/sub 3/N/sub 4/ film by the atomic oxygen. Good drivability is also demonstrated on a 0.12 /spl mu/m n-MOSFET device.