Influence of hydrogen on SiON thick film for silica waveguide deposited by PECVD and annealing effect

Silicon oxynitride (SiON) films containing various hydrogen concentrations were deposited in a plasma enhanced chemical vapor deposition (PECVD) reactor using SiH₄ and N₂O as precursor gases. In this work, the influence of annealing temperature on the optical and physical properties of SiON films is presented. It can be seen that the refractive index for the as-deposited SiON and annealed SiON films can be varied continuously between 1.4554 and 1.4513 at a wavelength of 1552 nm by using a prism coupler. The silicon content of the films is independent of the annealing temperature and for all layers it is approximately 33%. As annealing temperature increased, the oxygen content of the films increased from 64 to 66.2%, and the nitrogen content decreased from 1.98 to 0.02%.