PbTiOs ferroelectric thin films have been prepared on Si (001) by metal-organic chemical vapour deposition. The ai-grown films Were characterized by scanning electmn microscopy, x-ray diffraction and Raman spectroscopy. It is shown that the films were highly (001) oriented and had essentially the same lanice constants as the bulk single crystal. However, the %-grown films were subject to internal stress a shown by a downshift in the Raman modes when compared with a bulk single crystal.