Chemical depth profile of ultrathin nitrided SiO2 films

Abstract

Ultrathin nitrided ${\mathrm{SiO}}_2/\mathrm{Si}\text{(001)}$ films were studied using angle-resolved x-ray photoemission spectroscopy. The structure of the oxynitride depended on the nitridation process. Under one type of nitridation the film kept the structure of the ${\mathrm{SiO}}_2,$ with N assuming O sites. By taking advantage of the nonuniformity on the chemical depth profile, the Si $\text{2p}$ chemical shift was determined for those Si atoms bonded to three O and one N atom, and for those bonded to two O and two N atoms. The stoichiometry depth profile was recognized through a simple method that allowed the input of physical constrains.