X-ray characterization of MgO thin films grown by laser ablation on SrTiO3 and LaAlO3

Epitaxial thin films of MgO have been grown on single-crystal substrates of (1 0 0) oriented SrTiO3 and LaAlO3 by ablation of a Mg target in a molecular oxygen atmosphere using 1064 nm radiation from a Nd : YAC laser. Optimum growth was obtained with a substrate temperature of 500 degrees C and an ambient oxygen pressure of 5 x 10(-5) Torr during ablation. X-ray theta-2 theta plots show that MgO films grow (1 0 0) oriented on both substrates. Pole figures indicate that MgO grows cube-on-cube on the SrTiO3 substrate [MgO[1 0 0]//SrTiO3[1 0 0]]. On LaAlO3, the MgO lattice is rotated by 45 degrees in plane with respect to the substrate lattice, with MgO[1 1 0]//LaAlO3[1 0 0]. Symmetric and asymmetric area scans show that the MgO lattice is completely relaxed on both the SrTiO3 and LaAlO3 lattices. By depositing the MgO him without Q-switching the laser for a short initial period, a mixed (1 1 0) and (1 0 0) oriented MgO film was grown on LaAlO3. The (1 1 0) orientation is bicrystalline, with in-plane orientations of MgO[1 1 0]//LaAlO3[1 0 0] and MgO[1 0 0]//LaAlO3[1 0 0]. (C) 1998 Elsevier Science B.V. All rights reserved.