Effects of thickness and rf plasma oxidizing on structural and optical properties of SiOxNy thin films

SiOxNy thin films were prepared by electron beam evaporation on microscopic glasses and titanium substrates held at room temperature. The effects of thickness and rf plasma oxidizing power/time on structural and optical properties of SiOxNy thin films were examined. The experimental results indicated that the thickness affects the structural and optical properties of SiOxNy significantly. All the examined films with different thicknesses designated the presence of the hexagonal Si3N4 phase. As thickness changed the preferred orientation of hexagonal Si3N4 phase is changed. A decrease in transmittance and the optical band gap along with an increase in refractive index are observed with increasing the film thickness. The rf plasma oxidizing power/time also affects the structural and optical properties of SiOxNy significantly. The rf plasma treatment processes caused amorphization to the SiOxNy films. Slight increase in optical band gap values was observed with increasing rf power/time. Substantial increase in the refractive index, which could be attractive for optoelectronics applications, was obtained at moderate rf plasma processing powers/times.