Electrical and Structural Characterization of (002) Oriented Aluminum Scandium Nitride

In this paper, Al 0.8 Sc 0.2 N films with optimal orientation of (002) were deposited by DC magnetron sputtering in a N2 and Ar environment. (002) Al 0.8 Sc 0.2 N can be controlled by adjusting the substrate temperature. Al 0.8 Sc 0.2 N films grown were of the best quality with a smaller FWHM (0.22°) at 400°C. Based on this, the films grow with thickness spanning 364 nm to 945 nm. AFM analysis showed that roughness of Al 0.8 Sc 0.2 N films declined from 11 to 1.72 as thickness increased, indicating films became smooth while thickening. Dielectric permittivity of Al 0.8 Sc 0.2 N films also demonstrated a thickness dependence. The dielectric permittivity increased from 11.7 to 28.2 as thickness rose. Moreover, electric resistivity of Al 0.8 Sc 0.2 N was 22 MΩ due to its lower dielectric loss, which was slightly lower than that of pure AlN (28.2 MΩ). Our research is important for preparing high-quality piezoelectric films to improve performance of high-frequency devices.