Room-temperature epitaxial growth of AlN on atomically flat MgAl2O4 substrates

The authors have grown AlN films on atomically flat MgAl2O4(111) substrates at room temperature (RT) by pulsed-laser deposition. The in situ reflection high-energy electron diffraction image exhibits a streaky pattern, and the root-mean-square value of the surface roughness as measured by atomic force microscopy is as low as 0.45 nm, which indicates that single-crystalline AlN grows epitaxially on MgAl2O4 with a smooth surface, even at RT. Electron backscattered diffraction and x-ray diffraction measurements reveal that AlN {11- 20} shows a clear sixfold symmetry without 30 S rotational domains, and the epitaxial relationship is AlN [11-20]parallel to MgAl2O4 [0-11]. Grazing incidence angle x-ray reflectivity characterization indicates that the interfacial reaction between AlN and MgAl2O4 is completely suppressed in the case of RT growth and the heterointerface for the RT-AlN/ MgAl2O4 structure is abrupt and thermally stable. (c) 2006 American Institute of Physics.