The degradation (fatigue) of dielectric properties of ferroelectric Pb(ZrxTi1−x)O3 (PZT) and SrBi2Ta2O9 thin films during cycling was investigated. PZT and SrBi2Ta2O9 thin films were fabricated by metalorganic decomposition and pulsed laser deposition, respectively. Samples with electrodes of platinum (Pt) and ruthenium oxide (RuO2) were studied. The interfacial capacitance (if any) at the Pt/PZT, RuO2/PZT, and Pt/SrBi2Ta2O9 interfaces was determined from the thickness dependence of low-field dielectric permittivity (εr) measurements. It was observed that a low εr layer existed at the Pt/PZT interface but not at the RuO2/PZT and Pt/SrBi2Ta2O9 interfaces. In the case of Pt/PZT, the capacitance of this interfacial layer decreases with increasing fatigue while the εr of the bulk PZT film remains constant. This indicates that fatigue increases the interfacial layer thickness and/or decreases interfacial layer permittivity, but does not change the bulk properties. For the capacitors with RuO2/PZT/RuO2 and Pt/SrBi2Ta2O9/Pt structures, however, the εr does not change with ferroelectric film thickness or fatigue cycling. This implies no interfacial layer exists at the interfaces and which can be correlated to the observed nonfatigue effect. Additionally, the equivalent energy-band diagrams of these different capacitor structures were proposed to complement the proposed fatigue mechanism.

The retention and imprint properties of ferroelectric Pb(Zr0. 53Ti0. 47)O3 (PZT) and SrBi2Ta2O9 (SBT) thin films are studied. A simple characterization technique which consists of four measurement pulses is used to differentiate the retention and imprint effects. The high concentration of oxygen vacancies in PZT capacitors results in longer screening lengths and higher depolarization fields that worsen retention properties. A c‐axis preferred oriented SBT thin film deposited on Pt(100)/MgO(100) substrate contains a higher concentration of 180° domains and results in better retention properties due to the minimum ferroelastic effect. Ferroelectric SBT thin films with symmetric P–E hysteresis loops are chosen to study the imprint effect. The imprint process changes the symmetry of P–E hysteresis loop, which indicates the imprint process builds up an internal field within the ferroelectric thin films. Electrical charges trapped at electrode‐ferroelectric interfaces during the imprint stress are responsible for internal field build‐up and screen the spontaneous polarization internally.