The effect of oxygen partial pressure during cooling on lead zirconate titanate thin film growth by using rf magnetron sputtering method

The lead zirconate titanate (PZT) thin film was deposited on platinized sil icon wafer substrate by the rf magnetron sputtering method. In order to inv estigate the effect of cooling ambient, oxygen partial pressure was control led during cooling PZT films. The PZT films cooled at lower oxygen partial pressure had perovskite phase and pyrochlore phase in both as-grown and pos tannealed films, but in the PZT films cooled at higher oxygen partial press ure, pyrochlore phases were not detected by XRD. As the oxygen partial pres sure became lower during cooling, the capacitors had low values of remanent polarization and coercive field for as-grown films. The PZT capacitor with such a low value was recovered by postannealing in air, but its electrical properties had the same tendency before and after annealing. Microstructur e was also affected by cooling ambient. Higher oxygen partial pressure on c ooling reduced the number of very fine grains, and enhanced uniform grain d istribution. Fatigue characteristics were also enhanced by cooling at highe r oxygen partial pressure. However, the imprint was negligible irrespective of oxygen partial pressure upon cooling. The cooling procedure at higher o xygen ambients is believed to reduce the amounts of nonferroelectric second phases and oxygen vacancies. We find that oxygen partial pressure during c ooling is a considerable process parameter. Therefore, care should be taken in treating the parameter after depositing films.