Influence of Zr/Ti ratios on the deformation in the hysteresis loop of Pb(Zr,Ti)O3 thin film capacitors

Electric field shift and deformation in the polarization-electric field characteristics of Pb(Zr,Ti)O3 (PZT) thin film capacitors with various Zr/Ti ratios have been studied as a function of the annealing temperature after patterning the top sputter-deposited Pt electrode using reactive ion etch with Ar gas. A large field shift and a constriction in the hysteresis loops are observed, particularly in low Zr/Ti PZT films annealed below 400 °C. A strong blocking layer effect in unannealed capacitor is found to be related to the internal field caused by trapped charges near electrodes. As the Zr/Ti ratio decreases, the field shift increases and the annealing temperature at which the internal field disappears also increases.