Extrinsic conductivity in ferroelectric PZT film capacitors made by laser ablation deposition

Electrical properties of ferroelectric lead-zirconate-titanate (PZT) thin-f ilm devices are affected by the composition and structure of the PZT film i tself and also by the electrode material and the interface between the elec trode and ceramics. In this paper we consider capacitor structures with pla tinum thin-film electrodes (Pt/PZT/Pt/substrate) which typically have very high de resistivity, but stiffer from the polarization fatigue due to the h igh stress and oxygen vacancy build-up in the interface between the electro de and ceramic thin film. Both platinum electrodes and Nd-modified PZT (PNZ T) thin films were fabricated by the pulsed laser-ablation deposition and p ost-annealing heat treatments. The behaviour of the conductivity in the PNZ T thin-film capacitors was studied as a function of temperature and electri c field. Low-field resistivities of the order of 10(12) Ohm cm were measure d for the films at room temperature. Some differences were found in the cur rent-voltage characteristics between capacitor structures made on MgO(100) and oxidized silicon(100) substrates, respectively. assuming the Poole-Fren kel emission mechanism for the conduction, the activation energies of condu ction were obtained to be between 0.15 and 0.18 eV.