The dependence of aluminum nitride thin-film microstructure on the number of low-temperature plasma-enhanced atomic layer deposition process cycles

Abstract

Within the framework of the study, oriented aluminum nitride coatings were obtained on sapphire with orientation along the direction (0001) using the PEALD method at a temperature of 250°С and a number of deposition cycles from 80 to 500. The obtained samples were studied using ellipsometry, X-ray diffraction, and atomic force microscopy. It was shown that with an increase in the thickness of the coating, the refraction index increases to 2.02, and the root-mean-square (RMS) increases from 0.35 to 2.35 nm. All samples had (0002) and (0004) reflexes on X-ray diffractograms measured in the Bragg-Brentano geometry (θ/2θ-scan). On Δω-scans of the reflex (0002), the full width at half maximum (FWHM) amounted to 162 ± 7 arcsec