ELECTRON TRAPPING PROCESS IN FERROELECTRIC LEAD-ZIRCONATE-TITANATE THIN-FILM CAPACITORS

The effects of constant voltage stress on ferroelectric lead-zirconate -titanate (PZT) thin-film capacitors have been studied. Two stress eff ects are observed in the PZT capacitance-voltage (C-V) characteristics . The first is that the capacitance is reduced, and the second is a vo ltage shift of the C-V curve. These effects are found to depend on the stress electric field and the injected charge fluence. A correlation between the :;tress ef'fects and the electron trapping inside the film s is established. The injected charge fluence can be calculated from t he leakage current. The trapping efficiency, electron capture cross se ction, and the trap density are obtained from the measured injected ch arge influence and the C-V voltage shift. The calculated value of the electron capture cross-section sigma(T) is 1.89x10-(19) cm(2) and the neutral electron trap density N-T is 1.20x10(13) cm(-2) (C) 1998 Ameri can Institute of Physics.