Silicon oxidation and oxynitridation in the ultrathin regime: Ion scattering studies

The paper reviews our recent studies of the mechanistic and structural aspects of ultrathin (<5 nm) dielectric films (oxides, SiO₂, and oxynitrides, SiO_xN_y) thermally grown on silicon surfaces. High resolution medium energy ion scattering (MEIS) has been used as the primary tool in these studies. We discuss: (i) the growth mechanism of ultrathin films using isotopic (¹⁶O₂/¹⁸O₂) labeling methods, (ii) the initial stages of the interaction of oxygen with silicon surfaces under different temperature and pressure conditions, including a new roughening regime, (iii) the transition region near the oxide/substrate interface, and (iv) silicon oxynitridation in N₂O and NO.