Characteristics of ferroelectric Pb(Zr1-xTix)O3 thin film capacitors deposited on PtRhOy electrode barriers

We present the feasibility of single-layer PtRhO_y thin films as electrode barriers for ferroelectric Pb(Zr_1-xTi_x)O₃ (PZT) (x = 0.2 to 0.8) thin film capacitors. PtRhO_y thin films were deposited directly on n+ Si wafers by means of the reactive sputtering method. PtRhO_y/PZT/PtRhO_y/n+ Si capacitors showed well-saturated P-E hysteresis loops. The remanent polarizations, as well as the polarization loss after the switching repetitions, were varied with the ratio of Zr/Ti. Especially, Pb(Zr_0.4Ti_0.6)O₃ thin film capacitor showed the superior ferroelectric properties, such as the shape of P-E hysteresis loops and the behaviors of the polarization fatigue. The typical remanent polarization and the coercive field of this capacitor were 22 μC/cm² and 87 kV/cm, respectively, and the polarization loss was only less than 5 % after 10¹¹ switching repetitions. The chemical binding states of PtRhO_y films affected mainly the shape of P-E hysteresis loops. From the measurement of the depth profile and the microstructure of this capacitor, it could be convinced that single-layer PtRhO_x films behaved as high quality electrode barriers for PZT thin film capacitors.