• AlN;
  • MOVPE;
  • growth;
  • structure;
  • ion scattering;
  • spectroscopy


High-crystalline quality AlN layers with an atomically flat surface are grown on (0001) sapphire and 6H-SiC substrates by metal-organic vapor phase epitaxy at 1400 °C without low-temperature buffer layer. The polar direction of AlN layers is investigated by coaxial impact-collision ion scattering spectroscopy (CAICISS). For AlN growth on sapphire substrate, trimethylaluminum (TMAl) is supplied for 10 sec before introducing ammonia (NH3). For AlN growth on SiC substrate, TMAl and NH3 are supplied at the same time. The CAICISS spectrum of AlN layers is analyzed by measuring the dependence of the Al atoms signal intensity on the angle of ion beam incidence considering the shadowing and focusing effects for determining the polar direction of AlN layers. The CAICISS spectra clearly indicate the polar direction of AlN layers and both AlN layers are found to be had the Al-polarity. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)