Ion irradiation effects on optical properties of silicon nitride films

We have investigated effects on amorphous Si3N4 films induced by 100 keV Ne and N ions. Si3N4 films were deposited on SiO2-glass substrates by using reactive-RF-magnetron sputtering in N2 gas at room temperature. It is found that the absorbance in the UV region increases with increasing Ne ion dose, and the absorbance in the visible and infrared regions remains unchanged under Ne ion irradiation. For N ion irradiation, the absorbance in the visible and infrared regions increases with the ion dose, while the absorbance in the UV region does not exhibit a simple dose-dependence. It also appears that the refractive index exhibits a slight decrease for Ne ion irradiation and a decrease in a littlie bit complicated way for 100 keV N ion irradiation.