Growth of aluminum nitride on a silicon nitride substrate for hybrid photonic circuits

Aluminum nitride (AlN) is an emerging material for integrated quantum photonics with its excellent linear and nonlinear optical properties. In particular, second-order susceptibility $\chi^{(2)}$ allows single-photon generation. We have grown AlN thin films on silicon via reactive DC magnetron sputtering. The been characterized using X-ray diffraction, reflectometry, atomic force microscopy, scanning electron microscopy. crystalline properties of the improved by optimizing nitrogen to argon ratio power deposition process. diffraction measurements confirm fabrication high-quality c-axis oriented a full width at half maximum rocking curves 3.9 deg. 300-nm-thick films. Atomic microscopy reveal root mean square surface roughness below 1 nm. SiN us fabricate hybrid photonic circuits new approach that avoids challenging patterning AlN.