Low Stress, Anomalous Dispersive Silicon Nitride Waveguides Fabricated by Reactive Sputtering

Silicon nitride (SiN) waveguides are a promising platform for nonlinear photonic devices, as it offers a large bandgap, low two-photon absorption, CMOS-compatible fabrication methods and a significant nonlinearity [1,2]. Prominent applications are optical frequency comb generation [2] and supercontinuum generation [3]. These applications require waveguides with an anomalous group velocity dispersion in order to be efficient, which can be achieved by tailoring the waveguide dimensions [2,3]. Optical-quality SiN films are commonly deposited by LPCVD, however the high processing temperatures (> 800 ° C) can cause a high layer stress and crack formation. In this work we investigate reactive magnetron sputtering (PVD) as a method for low temperature (< 150 °C) deposition of SiN thin-films for optical waveguides.