High quality interpoly dielectrics deposited on the nitrided-polysilicon for nonvolatile memory devices

Abstract

In this study, a NH/sub 3/ with RTA N/sub 2/O process to incorporate nitrogen at dielectric/polysilicon interface has demonstrated an improvement in the integrity of the polyoxide. The polyoxide deposited on these nitrided polysilicon films with the additional N/sub 2/O densification on TEOS exhibits a lower leakage current, higher electric breakdown field, higher electron barrier height, lower electron trapping rate, and much higher charge-to-breakdown than the as-deposited polyoxide. SIMS result shows the incorporation of nitrogen at the polyoxide/poly-1 interface, which improves electrical properties in return. Polyoxides formed by this method can achieve a high breakdown field up to 19 MV/cm and charge-to-breakdown more than 20 C/cm/sup 2/. This process appears to be a very attractive alternative for conventional polyoxides.