Low Temperature SiN Waveguides Optimization for Photonic Platform

Integration of SiN on Si photonics platform becomes attractive for 3D integration of different waveguide levels in an optical routing circuit, and can be used for the realization of athermal devices needing specifics group index or group velocity dispersion. This paper is focused on the determination of the optical properties of different SiN deposited by PVD (Plasma Vapor Deposition) and PECVD (Plasma Enhanced Plasma Vapor Deposition) equipment with temperatures lower than 400°C to keep the compatibility with CMOS process. A set of designs including optical routing basic building blocks such as bends, MMI splitters and asymmetric Mach-Zehnder interferometer has been designed to determine propagation losses and propagation constants with high accuracy, for a large spectral range, around
$1.31\ \mu \mathrm{m}$
and
$1.55\ \mu \mathrm{m}$
[1]. Devices were manufactured on the STMicroelectronics DAPHNE (Datacom Advanced Photonics Nanoscale Environment) 300 mm Photonic R&D platform [2]. Comparison of experimental data with theoretical models will be made. Especially, we discuss the development of Finite Difference Full Vectorial mode solvers [3]–[4] coupled with the Mode Matching method. This method, used to simulate the propagation of light, also allows to evaluate side wall roughness contributions, Rayleigh scattering and absorption due to 2
^nd
harmonic vibrations of Si-OH and N-H bonds.