SIMS study of silicon oxynitride prepared by oxidation of silicon-rich silicon nitride layer

We proposed a novel process for fabrication silicon oxide–oxynitride–oxide structure for ULSI device applications. By deposition of silicon-rich silicon nitride and then following a thermal oxidation process, a good oxynitride layer was obtained. Secondary ion mass spectroscopy (SIMS) study reveals that the hydrogen content of nitride film at the interface can be reduced by more than 40% when compared to stoichiometric nitride. With this method, high nitrogen content oxynitride and smoother oxynitride/oxide interfaces result in the reduction of the interface charge trapping remarkably.