Epitaxial growth of 6H-AlN on M-plane SiC by plasma-assisted molecular beam epitaxy

A new AlN polytype is grown on M-plane 6H-SiC by plasma-assisted molecular beam epitaxy. A 6H stacking order is deduced from reflection high-energy electron diffraction patterns and the occurrence of an additional [1 1 6 0](6H) reflection in X-ray diffraction omega-20 scans. A predominant 6H stacking, intersected by thin lamellae with 2H stacking, is directly observed in high-resolution transmission electron microscopy. Atomic force microscopy (AFM) shows a stripe-like morphology with a roughness of 1.7 nm and a peak-to-valley distance of 12 nm over 25 m(2). The AlN films are partially relaxed and of good crystal quality as evidenced from X-ray diffraction omega-scans with a line width of 130 arcsec for both symmetric and asymmetric reflections. (c) 2006 Elsevier B.V. All rights reserved.