STRUCTURAL AND OPTICAL-PROPERTIES OF SILICON OXYNITRIDE ON SILICON PLANAR WAVE-GUIDES

Planar optical waveguides on thermally oxidized Si(lll) substrates have been made with rf magnetron sputtering deposition from a SiO2 target in a N2 and Ar reactive atmosphere. Reproducible guiding layers of silicon oxynitride with refractive index in the 1.6-1.9 range have been obtained changing deposition parameters. A detailed study of the film characteristics in terms of optical and chemical properties is reported. The films are a mixture of SiO2 and silicon oxynitride, with an extended intermixed region at the thermal SiO2buffer layer interface. Further annealing in N2 atmosphere (600° C < T < 1000° C) resulted in waveguide attenuation values lower than 1 dB/cm for l = 0.633 mm. © 1990 Optical Society of America.