SPECTROSCOPIC ELLIPSOMETRY STUDIES ON ION-BEAM SPUTTER-DEPOSITED PB(ZR, TI)O3 FILMS ON SAPPHIRE AND PT-COATED SILICON SUBSTRATES

Spectroscopic ellipsometry has been utilized to non-destructively dept h profile multi-ion-beam reactively sputtered lead zirconate titanate films. Some degree of inhomogeneity (in the form of low density layers or surface roughness) was found in all of the films examined. The evo lution in the structure and microstructure of such films during post-d eposition annealing was investigated with in situ spectroscopic ellips ometry. It was found that the onset of microstructural inhomogeneities was associated with the crystallization of the perovskite phase, and that the final film microstructure was dependent on the details of the annealing process. A model was developed to approximate the effect th at local density variations play in determining the net electrical pro perties of ferroelectric films. Depending on the configuration of the embedded porosity, it was demonstrated that microstructural inhomogene ities can significantly change the net dielectric constant, coercive f ield, and remanent polarization of ferroelectric films. It has also be en shown that low density regions near the film/substrate interface ca n result in apparent size effects in ferroelectric films.