Ferroelectric properties and fatigue behavior of heteroepitaxial PbZr_(1-x)Ti_xO_3 thin film fabricated by hydrothermal epitaxy below Curie temperature

摘要

A heteroepitaxial PbZr_(1-x)Ti_xO_3 (PZT) thin film was fabricated by means of hydrothermal epitaxy at 210℃ below Curie temperature without undergoing the paraelectric to ferroelectric phase transition. From transmission electron microscope and piezoresponse force microscope observations, it was confirmed that the fabricated PZT thin films had only a -c monodomain without an a domain in the as-synthesized state. The polarization-electric-field hysteresis curve and the fatigue behavior of the heteroepitaxial PZT capacitor with a Pt top and n-type semiconductor bottom electrode was observed. The remanent polarization 2P_r of the PZT capacitor was about 63 μC/cm~2. This value was much lower compared to that of the PbTiO_3 capacitor, which was also fabricated by means of hydrothermal epitaxy at 160℃ below Curie temperature. It was suggested that a lower polarization of the PZT capacitor was due to the nonswitchable interfacial layer grown in the initial growth stage. However, this layer did not exert an influence on the fatigue behavior of the PZT capacitor: the PZT capacitor with an ordinary Pt top electrode and a Nb-doped SrTiO_3 semiconductor bottom electrode revealed fatigue-free behavior in up to 10~(11) switching cycles.