Hyperthermal nitridation for ultrathin silicon oxynitride gate dielectrics

Heavy and shallow incorporation of N into ultrathin SiO2 films on Si was accomplished by different routes based on plasma or ion beam nitridation in the 3 to 1000 eV energy range, aiming at producing silicon oxynitride gate dielectrics. I-V and C-V characteristics of these nanostructures reveal significant improvements with respect to SiO2 films on Si of comparable thickness. Atomic-scale description of the ultrathin oxynitride films regarding N concentrations and depth profiles, as well as post-nitridation annealing effects, was accessed by nuclear reaction analysis, nuclear resonance profiling, and medium energy ion scattering. Correlations between dielectric performance and physicochemical characteristics are discussed.