Films of AlN were grown onto (00•1) or (10•2) sapphire substrates and (100) or (111) Si substrates, and were investigated by using plan-view and cross-sectional high-resolution transmission electron microscopic and X-ray diffraction techniques. The films were grown by means of metalorganic chemical vapor deposition. Various degrees of epitaxy were observed in the case of films which were grown onto -Al2O3 and Si substrates of differing orientation. The epitaxial relationship for (00•1) sapphire was found to be (00•1)AlN||(00•1)Sapphire, with [01•0]AlN||[1¯2•0]Sapphire. This was equivalent to a 30 rotation in the basal (00•1) plane. In the case of (10•2) sapphire substrates, the epitaxial relationship was (11•0)AlN||(10•2)Sapphire, with [00•1]AlN||[1¯0•1]Sapphire. The AlN films on (00•1) -Al2O3 were found to contain inverted domain boundaries and a/3<11•0> threading dislocations with an estimated density of 1010/cm2. The density of stacking faults which was found in AlN films was considerably higher in the case of (10•2), as compared with (00•1) substrates. The films on Si substrates were found to be highly textured c-axis oriented when grown onto (111)Si, and c-axis textured with a random in-plane orientation, on (100)Si.

K.Dovidenko, S.Oktyabrsky, J.Narayan, M.Razeghi: Journal of Applied Physics, 1996, 79[5], 2439-45