Fabrication of AlN films at low temperature by CS-MBE technique

The low-temperature deposition of AlN films by compound-source molecular-beam epitaxy (CS-MBE) technique was studied. AlN powder was used as the source and no additional nitrogen source was introduced during the deposition. X-ray photoelectron spectroscopy (XPS) results show that Al-N bonds were formed in the deposited films. It was clarified that the nitrogen atoms were supplied to the substrate from the AlN source and that the oxygen concentration in the deposited AlN films depended on the residual oxygen concentration in the AlN powder used as the source. The breakdown electric field of the AlN film was over 4.2 MV/cm, which indicates that the films deposited at a low temperature of less than 300 °C can be applied as the insulator in GaN-based electroluminescent devices. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)