Sr4Ru2O9 thin films have been grown by pulsed laser deposition (PLD) on Si [1 0 0] substrates, using a Sr2RuO4 target and high oxygen pressures. The growth conditions for a single-phased film were a substrate temperature of 700 degrees C, and an oxygen pressure of 300 mTorr. An oxygen pressure of 50 mTorr and a substrate temperature of 700 degrees C lead to the occurrence of nanograins of SrRuO3 at the surface of the Sr4Ru2O9 grains. The Sr4Ru2O9 growth is columnar, with a strong tendency to (0 0 l) texture. Planar defects parallel to the (h 0 0) and (0 k 0) planes are presented. The occurrence of these defects can be explained by an ordering of ruthenium atoms in the Sr4Ru2O9 structure. (C) 2008 Elsevier B.V. All rights reserved.