Highly epitaxial thin films of lanthanum aluminate (LaAlO3) have been obtained on strontium titanate (SrTiO3) substrates by means of atomic layer deposition using La(thd)(3) (Hthd = 2,2,6,6-tetramethylhepta-3,5-dione), Al(CH3)(3) and ozone as precursors. The system shows a near linear relationship between pulsed and deposited composition. Thin films with stoichiometric composition have been subject to thermal annealing at 650 degrees C under oxygen atmosphere, thereby achieving epitaxial films on Ti-O-terminated substrates of SrTiO3. The thin film vertical bar vertical bar substrate epitaxial relationship is determined to be LaAlO3(100)vertical bar LaAlO3[100]vertical bar vertical bar-SrTiO3(100)vertical bar SrTiO3[100] by use of synchrotron radiation. Selected films were also deposited on LaAlO3(100) to achieve homoepitaxy. This resulted in the observation of split peaks for high q-reflections, pointing towards slight differences in stoichiometry. For ultrathin films, Bragg satellites were observed around the specular reflections, coming from either surface-or interface reconstruction. (C) 2013 Elsevier B. V. All rights reserved.