Effects of post‐deposition annealing on chemical composition of SiNx film in SiO2/SiNx/SiO2/Si stacked structure

To systematically evaluate the quality of SiN x films in multi‐stacked structures, we investigated the effects of post‐deposition annealing (PDA) on the film properties of SiN x within the SiO 2 /SiN x /SiO 2 /Si stacked structure by performing X‐ray photoelectron spectroscopy (XPS), X‐ray reflectivity (XRR), Fourier transform infrared (FT‐IR) spectroscopy, and scanning transmission electron microscope–electron energy loss spectroscopy (STEM‐EELS) analyses. The XPS results showed that PDA induces the oxidation of the SiN x layer. In particular, new finding is that Si‐rich SiN x in the SiN x layer is preferentially oxidized by PDA even in multi‐stacked structure. The XRR results showed that the SiN x layer becomes thinner, whereas the interface layer between the SiN x layer and Si becomes thicker. It is concluded by STEM‐EELS and XPS that this interface layer is SiON layer. The density of N–H and Si–H bonding within the stacked structure strongly depends on the PDA temperature. Our study helps elucidate the properties of SiN x films in stacked structures from various perspectives.