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

In this paper, Al
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N films with optimal orientation of (002) were deposited by DC magnetron sputtering in a N2 and Ar environment. (002) Al
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N can be controlled by adjusting the substrate temperature. Al
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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
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N films declined from 11 to 1.72 as thickness increased, indicating films became smooth while thickening. Dielectric permittivity of Al
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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
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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.