AlN thin films were grown on HF-etched Si͑111͒ substrates at 400-600°C by plasma source molecular beam epitaxy. Reflection high energy electron diffraction and transmission electron microscopy studies show that AlN films grown at 400°C form an initial amorphous region at the interface, followed by c-axis oriented columnar grains with slightly different tilts and twists. AlN films grown at 600°C showed a significantly reduced amorphous region near the interface promoting an epitaxial growth of

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... N with AlN͓0001͔ ʈ Si͓111͔ and AlN͓0110͔ ʈ Si͓112͔ orientations. However, all the films show numerous defects such as stacking faults, dislocations, and grain boundaries.