Design, fabrication and characterization of SiOx/SiON/SiO2/Si structures for passive optical waveguides realization

SiON is a suitable material for the implementation of photonic integrated circuits with a middle refractive index contrast for the visible and near infrared region. The paper presents the design, fabrication and characterization of SiON/SiO2/Si structures for passive optical waveguides realization with designed refractive index contrast 0.13. This refractive index contrast allows fabrication of strip SiOx/SiON/SiO2/Si waveguides with waveguide band losses bellow 0.01dB/cm at 150um waveguide radius. SiON and SiOx layers were fabricated by plasma-enhanced chemical vapor deposition techniques. The plasma-enhanced chemical vapor deposition technological parameters were tuned and optimized for designed refractive index contrast 0.13 and designed waveguide thickness 2.5 m. The refractive index of fabricated SiON layers were measured by optical ellipsometry.