Abstract: A depth profiles analysis of the irradiation effect of Si₃N₄/SiO₂ double-gate medium under ⁶⁰Co-γ ray irradiation has been carried out by using the X-ray photoemission spectroscopy(XPS) method, with Ar⁺ ion etching. The experimental results show that there is distinct interface region between Si₃N₄ and SiO₂ as well as between SiO₂ and Si, respectively, and after irradiation, a shift to Si₃N₄/SiO₂ interface of the center SiO₂/Si interface region occurs. In addition, the SiO₂/Si interface region is broadened. A great decrease in concentration of Si middle state located in a region from SiO₂/Si interface to Si substrate is induced by irradiation. With the same bias, the amount of break-bond of Si middle states located in SiO₂/Si inteface region increases with increasing radiation doses, and it is found that the bias on the sample radiated plays an obvious role in breaking the bonds of Si middle states. Finally a discussion on experimental results is presented.

Key words: XPS, Si₃N₄, SiO₂/Si, Si middle state, irradiation