Relaxation of the Si lattice strain in the Si(001)-SiO₂ interface by annealing in N₂O

It was clearly observed with medium energy ion scattering spectroscopy that the strain in the Si(001)-SiO₂ interface of thermal oxides is relaxed by annealing in N₂O. The strain relaxation could be correlated with the improved hot-electron hardness of the nitrided oxides compared with the thermal oxides. Based on the direct observation of the strain relaxation, it is suggested that the incorporated N atoms at the interface release the strain and increase the immunity of trap generation under the current stress.