MBE growth and ultrahigh temperature processing of high-quality AlN films

Molecular beam epitaxial growth of AlN on sapphire and 6H-SiC has been performed utilizing mono-energetic activated nitrogen ion beams (2-80 eV kinetic energies). The growth temperature of AlN in MBE is found to be limited by the sticking coefficient of incident reactants. The combination of elevated growth temperatures (1050-1150 °C), high kinetic-energy reactive nitrogen (>40 eV) and post-growth thermal processing (1150-1350 °C) produces high-quality AlN thin-films with narrow rocking curve widths (<2 arcmin) and low dislocation densities (< approximately 3×10⁸ cm^-2). In contrast, the use of in-situ step anneals during synthesis did not achieve similar quality materials.