Characterization of ALN thin films deposited by DC reactive magnetron sputtering

Abstract

A set of AlN thin-films was prepared by reactive magnetron sputtering at room temperature. The purpose of this work was to study the effect of oxygen impurities on the structural and optical properties of AlN films. The structural and optical properties of the resulting films were characterized using X-ray diffraction (XRD) and spectroscopic ellipsometry, respectively. Depending on the deposition conditions, films can be hexagonal (wurtzite, P6$_{3}$m3) or cubic (zinc blende, Fm3m) in their microstructure. From the optical measurements, the ellipsometric parameters ($\psi $,$\Delta )$ and the real refractive index as a function of energy were obtained. From the ellipsometric measurements, a model of the Lorentz single-oscillator was employed to estimate the optical band gap, $E_{g}$.