2H–AlN(0001) layers have been grown on Si(111) by reactive magnetron sputtering from an Al target in Ar+N2gas mixtures at temperaturesTs=400–900 °C. Variations in reactive gas consumption, target voltage, and current–voltage characteristics versus nitrogen partial pressure were used to determine deposition parameters required to yield stoichiometric AlN with growth rates ≥2 &mgr;m h−1. High‐resolution cross‐sectional transmission electron microscopy (XTEM) analyses of films grown at 900 °C showed that the initial 6–8 monolayers were (111)‐oriented cubic 3C before transforming to the (0001)‐oriented 2H polytype. The epitaxial relationship was found by XTEM and x‐ray diffraction (XRD) to be 2H–AlN(0001)//3C–AlN(111)//Si(111) with 2H–AlN[12¯10]//3C–AlN[110]//Si[110]. High‐resolution XRD &ohgr;−2&THgr; and &ohgr; rocking curve widths for films grown atTs=900 °C were 70 and 500 arc sec, respectively, the lowest values yet reported. ©1995 American Institute of Physics.