Epitaxial growth of AlN and Al0.5Ga0.5N layers on aluminum nitride substrates

High quality epitaxial AlN and AlxGa1-xN layers have been grown by organo-metallic vapor-phase epitaxy on single crystal a-face AlN substrates. Here we report the characterization of these layers using Rutherford backscattering/ion channeling spectroscopy, atomic force microscopy, double crystal x-ray diffraction, and preliminary electrical results. Ion channeling along the [11 (2) over bar 0] axis gave a minimum yield of 1.5% for an AlN layer and 2.2% for an Al0.5Ga0.5N, indicating excellent crystal quality. A resistivity of 20 Omega cm and a mobility of 20 cm(2)/V s was measured in a Si-doped, 1-mu m-thick Al0.5Ga0.5N grown epitaxially on the AlN substrates. (C) 2000 American Institute of Physics. [S0003-6951(00)01808-8].