PECVD deposition and characterization of silicon oxynitride for optical applications

Abstract

Silicon oxynitride (SiON) films have been found to possess extremely useful properties for optical applications. In optoelectronics, a major advantage of this material is the ability to tune the refractive index from 1.45 to 2.00, allowing designers the flexibility to custom tailor and optimize the refractive index value in the targeted optical device. In addition, its minimum allowable bending radius is much lower compared to other silica materials. This opens up the possibility of miniaturizing integrated photonic systems. Moreover, silicon oxynitride prepared using Plasma Enhanced Chemical Vapor Deposition (PECVD) can be deposited at high growth rates while exhibiting good homogeneity with wide refractive index tuning range making it a well-suited core layer for planar waveguide technologies and microphotonic devices. In this research work, the deposition process and the properties of SiON are discussed. The obtained refractive index as well as the X-ray photoelectron spectroscopy (XPS) analysis are highlighted. Furthermore, FTIR results as a function of the process parameters are presented and their influence on the film properties is discussed.