Composition control of SBN thin films deposited by PLD on various substrates

Thin films of SrBi2Nb2O9 (SBN) have been grown on both Pt/Ti/SiO2/Si and (100)MgO substrates by pulsed laser deposition. In the Sr-Bi-Nb-O system, the loss of bismuth during the process due to its volatility results obviously in a non-respect of the stoichiometry of the films and the presence of secondary phases. In order to maintain the right composition of the films, two different ways were experimented. On Pt/Ti/SiO2/Si, a sequential deposition from home-made Bi2O3 and SBN sintered targets as well as the use of Bi-enriched targets allows to obtain stoichiometric ferroelectric films. Various parameters like deposition time and periodicity of the Bi2O3 and SBN layers are of first importance. On ( 100)MgO which promotes SBN epitaxial growth, this sequential deposition is not suitable and we succeeded in the control of the Bi/(Sr+Nb) ratio only by using Bi-enriched targets. (C) 2001 Elsevier Science Ltd. All rights reserved.