La- and V-substituted thin films of Bi4Ti3O12 (Bi-3.25,La-0.75)(Ti-2.97,V-0.03)O-12 (BLTV) were prepared by metalorganic chemical vapor deposition on (1 1 1)Ir/TiO2/SiO2/Si, (1 1 1)Pt/TiO2/SiO2/Si, and (1 1 1)Pt/Ti/SiO2/Si substrates at 600degreesC. Film orientation was investigated by X-ray reciprocal space mapping together with the conventional X-ray 2theta-theta scan. All the films consisted of a single phase of BLTV and showed mainly (0 0 1)- and (1 1 7)-orientations on a 2theta-theta scan. However, it was confirmed that the weak (1 1 7)-, strong (1 0 4)-, and (1 1 1)-centered orientations; (1 1 0), (1 1 1), and (112) orientations, were ascertained for the films deposited on (1 1 1)Pt/TiO2/SiO2/Si, (1 1 1)Pt/Ti/SiO2/Si, and (1 1 1)Ir/TiO2/SiO2/Si substrates, respectively, by the X-ray reciprocal space-mapping measurement. These tendencies were in response to the ferroelectric property of the film. As a result, orientation of the film strongly depended on the kinds of substrates and the X-ray reciprocal space mapping is the useful method to investigate the orientation of the bismuth-layer-structured ferroelectric thin films. (C) 2002 Elsevier Science B.V. All rights reserved.