Structural analysis of N‐polar AlN layers grown on Si (111) substrates by high resolution X‐ray diffraction

Abstract

AbstractCrack‐free high quality N‐polar AlN epitaxial layers were grown on Si (111) substrates by plasma‐assisted molecular beam epitaxy in the temperature range of 780–880 °C. The streaky 1×3 reflection high energy electron diffraction pattern was observed at room temperature for all AlN samples indicating N‐polarity of epilayers. The polarity of samples was also confirmed by KOH etching studies. Structural properties of as‐grown samples were carried out by high resolution X‐ray diffraction, scanning electron microscopy, and atomic force microscopy. The Williamson‐Hall plots of the rocking curves widths were employed in order to study the mosaicity, dislocation density, and level of stress as a function of growth temperature. The 250 nm thick AlN sample grown at 830 °C yields the best crystalline quality, smooth surface morphology, and smallest root mean square roughness. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)