Synthesis, Characterization and Optical Constants of Silicon Oxycarbide

¹ Dipartimento di Elettronica, Informazione e Bioingegneria (DEIB), Politecnico di Milano, via Ponzio 34/5, 20133 Milano Italy
² Department of Telecommunications Engineering, Mehran University of Engineering & Technology, Jamshoro 76062, Pakistan
³ Department of Metallurgy and Materials Engineering, Mehran University of Engineering & Technology, Jamshoro 76062, Pakistan
⁴ Polifab, Politecnico di Milano, via Giuseppe Colombo 81, 20133 Milano Italy

^* Corresponding author: faisalahmed.memon@polimi.it

Published online: 23 March 2017

Abstract

High refractive index glasses are preferred in integrated photonics applications to realize higher integration scale of passive devices. With a refractive index that can be tuned between SiO₂ (1.45) and a-SiC (3.2), silicon oxycarbide SiOC offers this flexibility. In the present work, silicon oxycarbide thin films from 0.1 – 2.0 μm thickness are synthesized by reactive radio frequency magnetron sputtering a silicon carbide SiC target in a controlled argon and oxygen environment. The refractive index n and material extinction coefficient k of the silicon oxycarbide films are acquired with variable angle spectroscopic ellipsometry over the UV-Vis-NIR wavelength range. Keeping argon and oxygen gases in the constant ratio, the refractive index n is found in the range from 1.41 to 1.93 at 600 nm which is almost linearly dependent on RF power of sputtering. The material extinction coefficient k has been estimated to be less than 10^-4 for the deposited silicon oxycarbide films in the visible and near-infrared wavelength regions. Morphological and structural characterizations with SEM and XRD confirms the amorphous phase of the SiOC films.