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.

Electrical and structural properties of ultrathin SiON films on Si prepared by plasma nitridation

“…11 Values as low as ϳ10 10 cm −2 have been achieved using such annealing procedures. 12 The increase in D it following nitridation can degrade the channel mobility. It can also cause reliability issues such as a deterioration of the negative bias temperature instability.…”

Ultrathin decoupled plasma nitridation SiON gate dielectrics prepared with various rf powers

“…The other possible way to solve these problems is to use silicon oxynitride ͑i.e., SiON͒ as the gate dielectric. 7 It has been shown that SiON has a relatively large dielectric constant so that we can achieve a larger equivalent oxide thickness. Compared with SiO 2 , SiON gate dielectric can also suppress boron penetration more effectively.…”