Thin TiN films were grown by reactive dc magnetron sputtering on single-crystalline MgO(001) substrates at a range of temperatures from room temperature to 600 degrees C. Structural characterization was carried out using x-ray diffraction and reflection methods. TiN films grow epitaxially on the MgO substrates at growth temperatures of 200 degrees C and above. The crystal coherence length determined from Laue oscillations and the Scherrer method agrees with x-ray reflection thickness measurements to 6% and within 3% for growth temperatures of 200 and 600 degrees C, respectively. For lower growth temperatures the films are polycrystalline but highly textured and porous. (C) 2010 American Vacuum Society [DOI: 10.1116/1.3357303]