Novel fabrication process to realize ultra-thin (EOTÂ =Â 0.7 nm) and ultra-low-leakage SiON gate dielectrics

We have investigated the reaction mechanism of the nitridation process based on first principles calculations and experimental results. We found that oxidation-resistant Si3N4 film can be formed by uniformly arranging 3-fold coordinated N atoms into Si sub-surface layer, and we successfully incorporated O atoms into the SiN/Si interface with minimum disruption of SiN structures. We have realized a high-quality ultra-thin gate SiON film with an equivalent oxide thickness of 0.7 nm and a leakage current of 95 A/cm2, 1/10 or less than that of traditional SiON films. Mobility is not reduced to less than 89% of an ideal SiO2 film.