Robust Ultrathin Oxynitride with High Nitrogen Diffusion Barrier near its Surface Formed by NH3 Nitridation of Chemical Oxide and Reoxidation with O2

Abstract

We have proposed an approach for growing robust ultrathin oxynitride using conventional thermal processes with the capability of preventing boron penetration. In this method, we obtain oxynitride with high nitrogen concentration (≈13 at. %) on the top and low interface state density (Dit=2×1010 cm-2 eV-1). The films demonstrate excellent properties in terms of low Dit, low leakage current, high endurance in stressing and superior boron diffusion blocking behavior. This method does not involve any additional capital equipment [such as decoupled plasma nitridation (DPN) or remote plasma nitridation (RPN)] or gas (NO or N2O). In addition, it obtains high-quality oxynitride film with low thermal budget. Most importantly, this process is simple and fully compatible with current process technology. It would be important and interesting for process engineers engaged in the field of gate dielectrics. It is suitable for the next generation of ULSI technology.