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Barium titanate (BaTiO 3 ) films were prepared on (100)Pt/(100)MgO substrates by metal-organic chemical vapor deposition (MOCVD). The effects of deposition temperature (T dep ) and O 2 partial pressure (P O 2 ) on the microstructure and dielectric properties of the films were investigated. The BaTiO 3 films prepared at T dep = 873 K showed a randomly orientated granular structure, while those prepared at T dep = 973 K showed a significant (001) orientation with a columnar structure. The grain size was strongly affected by P O 2 and showed the maximum at P O 2 = 66 to 93 Pa. The dielectric constant increased from 93 to 640 with increasing grain size from 20 to 130 nm, showing a broad peak at 350 to 380 K.

Ba(Ti 0:85 Zr 0:15 )O 3 films were prepared at 973 K on (100)Pt/(100)MgO substrates by metalorganic chemical vapor deposition (MOCVD), and their dielectric properties were investigated. The dielectric constant (" 0 ) of the film changed depending on the ac electric field (E ac ) and frequency at temperatures below 400 K. The " 0 showed a broad maximum at a specific temperature (T M ) that decreased from 370 to 330 K with increasing E ac from 0:15 Â 10 5 to 15 Â 10 5 VÁm À1 . The film exhibited ferroelectric characteristics with remanent polarization (2P r ) of 3 Â 10 À2 CÁm À2 and coercive field (2E C ) of 14 Â 10 5 VÁm À1 .

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