Keywords: A1. Domain twist A1. Local strain A1. X-ray microdiffraction A3. Hydride vapor phase epitaxy B1. Nitrides B2. Semiconducting III–V materials a b s t r a c t X-ray microdiffraction (XRMD) measurements using the AlN 2201 and 1210 Bragg reflections were performed to determine the cross-sectional distribution of local residual strain and twisting of crystal domains for a thick AlN film grown on a trench-patterned AlN/α-Al 2 O 3 template. The distribution of the strain components in the [0001] and ½1120Š directions, which are perpendicular to the trench lines, was strongly influenced by the presence of voids caused by the trench pattern. The strains in the ½1100Š and ½1120Š directions determined using the two Bragg reflections were found to be significantly different, and this was shown to be the result of twisting of the crystal domains about the [0001] axis under the influence of anisotropic shear stress in the prismatic planes. & 2013 Elsevier B.V. All rights reserved.