Ab initio analysis on stability of metal atoms in β-Si_3N_4/Si structure

摘要

We have analyzed the metal behavior in the SiN/Si structure with density functional theory. The structure of SiN film was assumed to be a β-Si_3N_4 single crystal. We separated the SiN/Si structure into three models: first, β-Si_3N_4 bulk model for inside the SiN thin film; second, interface model of β-Si_3N_4Si, and third, Si bulk model for Si substrate. Furthermore, Cr, Fe, Ni, Cu or W atom was placed in each model and the geometry optimization was performed to evaluate the formation energy. The order of the calculated formation energy of each metal in β-Si_3N_4/Si structure is W > Cr, Fe > Cu, Ni. By using the calculated values of formation energy of these metals, we explained the experimental results to some extent.