Physical origin of conduction in PZT thin films

Abstract

Leakage conduction of Pt-Pb(Zr_xTi:_1−x)O₃-Pt capacitors is studied by means of different measuring techniques and analyzed in terms of semiconductor properties of the system. Based on the experimental data, it is concluded that two different regimes of carrier injection (with the critical electric field of the crossover between these regimes being independent of the measuring technique) are responsible for true leakage conduction in Pt-Pb(Zr_xTi_1−x)O₃-Pt films. For interpretation of the experimental results a Space-Charge-Influenced-Injection model which takes into account both role of charge of depletion in the bulk of the film and injection through the blocking contact is proposed. This model describes well the main features of the observed current-voltage characteristics and provides a reasonable fit for the current-voltage curves measured at elevated temperatures, the values of the fining parameters being in a good agreement with the results of other studies. The presented study provides insight in the physical nature of leakage conduction of Pt-Pb(Zr_xTi_1−x)O₃-Pt system and suggests a method for analyzing its semiconductor parameters by means of conduction measurements.

Keywords:

• PZT film
• conduction
• injection
• space-charge
• depletion