Fabrication of planar SiON optical waveguide and its characterization

Abstract

Silicon oxynitride (SiON) was deposited as a core layer on a silica (SiO 2 ) under-cladding layer by using plasma enhanced chemical vapor deposition (PECVD). The refractive index of the SiON core layer was varied between 1.45 and 1.78 by changing the gas flow ratio of SiH 4 , N 2 O and NH 3 . Etching experiments were performed using a dry etching equipment to fabricate the SiON core. An optical planar waveguide with a core and under-cladding thicknesses of 6 μm and 8 μm, respectively, and a refractive index contrast (∆n) of 7 % has been fabricated.