4 February 2020
CEA-Leti unveils silicon nitride 200mm platform for developing ultralow-loss, high-power photonics in UV through mid-IR wavelengths
At Photonics West 2020 in San Francisco, CA, USA, micro/nanotechnology R&D center CEA-Leti of Grenoble, France unveiled a silicon nitride (Si3N4) 200mm platform for developing ultralow-loss, high-power photonics in ultraviolet (UV) through mid-infrared wavelengths (‘Ultralow-loss tightly confining Si3N4 waveguides and high-Q microresonators’, Optics Express, vol 27 (2019), issue 21, p30726). Available in CEA-Leti’s SiN platform in a multi-project-wafer program, the breakthrough targets designers in integrated quantum optics, LiDAR (light detection and ranging), biosensing and imaging whose projects require ultralow propagation losses and high power handling capability.
The ultralow-loss SiN layer is available for multi-level photonic circuits. It can be combined with a heater layer and a silicon layer in a unique platform to integrate passive and active components, such as Mach-Zehnder interferometers (MZI), multi-mode interferometers (MMI), ring resonators, filters, arbitrary waveform generators (AWG), modulators and photodiodes. This ultralow-loss layer can also present a local opening for biosensing applications.
“Companies requiring III-V/SiN laser co-integration or working on integrated quantum photonics for communication and computing applications can use this unique capability to combine those ultralow-loss properties with high-thickness SiN in a CMOS-compatible photonics platform,” says business developer Eléonore Hardy. “This breakthrough process will contribute to the Quantum 2.0 revolution and will lead to photonic devices that actively create, manipulate and read out quantum states for the emergence of quantum computing, imaging, sensing, communication and clocks,” she believes.
The best-in-class performance obtained with an 800nm-thick SiN layer includes a 2x reduction in propagation loss, with average attenuation coefficients as low as 3dB/m for high-confinement 1.6µm-wide, 800nm-high strip waveguides across the S-, C- and L- optical-wavelength bands. CEA-Leti also improved aging in the photonics devices and produced high-Q photonic micro-resonators with intrinsic quality factors approaching 107 across the C-band and reduced feature size.
Deposition of SiN uses CEA-Leti’s high-quality twist-and-grow, low-pressure chemical vapor deposition (LPCVD) technique that deposits relatively thick, pure and stoichiometric SiN with good thickness uniformity, unlike standard chemical vapor deposition techniques, it is claimed. Furthermore, a multi-step chemical-physical annealing smoothed the sidewall roughness of SiN waveguides, which further decreased propagation losses.