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 mu m. The refractive index of fabricated SiON layers were measured by optical ellipsometry.