Linear and nonlinear properties study of silicon nitride films for integrated photonics

Silicon nitride has been used in the silicon photonics industry as an adequate alternative for manufacturing waveguides with good behavior for integrated nonlinear optics applications. In this work, we study the optical properties of silicon nitride thin films grown by the radiofrequency magnetron sputtering technique in a reactive process at room temperature. To determine the features of our material, we grow near to stoichiometric silicon nitride modifying several synthesis parameters, and we studied the variation of their linear and nonlinear properties. Employing the z-scan technique, we have found that our material's nonlinear refractive index is about 1.04 x 10-15 m2/W, measured with femtosecond pulses centered at 0.8 mu m. We also studied the chemical composition through X-ray photoelectron spectroscopy and we confirm through X-ray diffraction that our thin films are not crystalline. The results suggest our material is a promising option for their use in nonlinear and quantum optics in integrated platforms.