The crystallinity and microstructures of MOCVD AIN films deposited on Si(lll) substrates with and without a buffer layer(s) were determined. The buffer layers were a thin 3C-SiC(III) layer produced via conversion of a Si(lll) surface and a film stack consisting of graded-AlxGa1-xN/GaN/3C-SiC. A randomly oriented polycrystalline AIN film was obtained when this material was deposited directly on the Si(lll). The use of a buffer layer led to the growth and coalescence of highly oriented AIN films produced by the coalescence of grains having average misalignments along the c-axis of 1.8 degrees and that on the c-plane of 3.3 degrees. The grains exhibited strongly faceted tips. The 2H-AlN(0001) films grown on a 3C-SiC(111) buffer layers showed adequate crystal perfection for use as a template for growth of single-crystal GaN and/or AlxGa1-xN films.