Electronic structure of thin film silicon oxynitrides measured using soft x-ray emission and absorption

The elementally resolved electronic structure of a thin film silicon oxynitride gate dielectric used in commercial device fabrication has been measured using soft x-ray emission and absorption spectroscopies. The ${\mathrm{SiO}}_x{\mathrm{N}}_y$ was grown by annealing ${\mathrm{SiO}}_2$ in ${\mathrm{NH}}_3.$ Soft x-ray emission and soft x-ray absorption were used to measure the valence and conduction band partial density of states in the interfacial region of both the nitrogen and oxygen states. The elementally specific band gap for the $\mathrm{O}\text{\hspace{0.05em}2p}$ states was measured to be 8.8 eV in the interfacial region, similar to that of pure ${\mathrm{SiO}}_2.$ The elementally specific band gap for the $\mathrm{N}\text{\hspace{0.05em}2p}$ states in the interfacial region was measured to be approximately 5 eV.