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International audience; Silicon nitride platforms based on ultra-low loss tightly confining waveguides present a great interest for a wide range of applications. We present our 200mm platform based on 800nm-thick LPCVD Si3N4 with optical losses below 5dB/m. It is completed with a set of photonic components specially developed for this platform: grating and edge fiber couplers, directional couplers, MMI, Y-junction, racetrack resonators and an AWG multiplexer. The Si3N4 platform and its device library are the basic building blocks for more complex circuits targeting advanced applications: LiDAR, microwave optics, quantum photonics, neuromorphic computing and sensors.

Roughness has always been a key detractor of the optical losses within the silicon photonics devices. With scaling at 300mm wafer, there is an introduction of new tools such immersion lithography scanner, OPC technique that can help to drive furthermore the optical losses reduction. This study will detail the work done on characterizing multiple steps of the process (Lithography, Etch, Annealing) and using roughness tools such LER (Line Edge Roughness), LWR (Line Width Roughness) and finally PSD (Power Spectral Density) to understand the main detractor of the optical losses at each step. These data will be extracted using SEM imaging from VeritySEM 6i.