Observation on plasmons in double interfaces of Si3N4/SiO2/Si irradiated by 60Co

The first level plasmons of Si in pure Si state, SiO2 state and Si3N4 state (corresponding to bonding energy of 116.95, 122.0 and 127.0 eV respectively) were investigated directly with X-ray Photoelectron Spectroscopy (XFS) before and after 60Co irradiation. the experimental results demonstrate that there exist two interfaces, one consists of plasmons of Si in Si3N4 state and in SiO2 state, while the other is made of plasmons of Si in pure Si state and in SiO2 state. When the Si3N4/siO2/Si samples were irradiated by 60Co, the interface at Si3N4/SiO2 was extended and at the same time the center of this interface moved towards the surface of Si3N4. The concentration of plasmons in SiO2 state was decreased at the SiO2/Si interface, and effects of radiation bias field on plasmons in the SiO2/Si interface were observable. Finally, the mechanism of experimental results is analyzed by the quantum effect of plasmons excited by photoelectrons. (authors)