Epitaxial growth of aluminum nitride on Si(111) by reactive sputtering

We have studied growth of aluminum nitride (AlN) on Si(111) by ultra-high vacuum (UHV) reactive dc-magnetron sputtering under a mixture of Ar and N ₂ gases. As-grown films have been examined by x-ray diffraction, Auger electron spectroscopy (AES), and transmission electron microscopy (TEM). Results of x-ray diffraction show texturing with AlN [0001]//Si[111]. Complementary TEM examinations observe epitaxy of AlN on Si(111), with AlN[112̄0]//Si[22̄0]. The AlN/Si interface is sharp and flat. The lowest substrate temperature required to achieve epitaxy T_epi has been determined to be ∼600°C. A dislocation density in AlN film grown at 700°C has been estimated to be ∼3×10^{1 1}/cm².