An on-chip nonlinear optical device that uses AlScN films to undergo scalable manufacturing processes

Nonlinear photonics is a growing field that uses chip-sized devices to control light signals. These devices are used in telecommunications, biosensing, and quantum computing. For known nonlinear materials, there are few options for affordable, large-scale production of nonlinear photonic devices because many are either too weak, or not compatible with CMOS processing, the primary fabrication process used in modern-day electronics.  As a result, there is a need for new nonlinear materials that can be used in scalable CMOS processes.

This technology uses aluminum scandium nitride (AlScN) films as a nonlinear material to make efficient CMOS-compatible photonic devices. Because most contemporary microchips are fabricated using CMOS processes, devices designed with CMOS-compatible AlScN films can be made in the same environment, lowering production costs.

AlScN exhibits stronger second-order optical nonlinearity than currently used materials, such as AlN. It can also be grown directly on CMOS devices due to its low sputtering temperature. The CMOS-compatibility of AlScN makes it a viable candidate to interface with silicon photonic devices as a strongly nonlinear material. In a proposed photonic device design, silicon nitride is used to define a waveguide and ring resonator structure on top of an AlScN film. When interfaced with electrical devices, the optical resonance shifts, enabling electro-optic modulation.

• Highly scalable and easy to interface with silicon photonic devices due to its CMOS-compatibility
• Can be used to make efficient electro-modulators as it exhibits a second-order optical nonlinearity 12 times higher than other CMOS-compatible nonlinear materials such as AlN and 2 times higher than other strongly nonlinear materials such as lithium niobate (LN)