Low voltage saturation of Pb(ZrxTi1-x)O-3 films on (100)Ir/(100)(ZrO2)(1-x)(Y2O3)(x)/(100)Si substrate structure prepared by reactive sputtering

The 37- to 280-nm-thick epitaxial (001)Pb(ZrxTi1-x)O-3 (PZT) films were dep osited by reactive sputtering on the (100)Ir/(100)(ZrO2)(1-x)(Y2O3)(x)(YSZ) /(100)Si substrate structures. We investigated the film thickness and cryst alline quality dependences of the ferroelectrical property of the PZT film from a viewpoint of low voltage saturation. The samples were dipped in 61% HNO3 solution prior to forming the top IrO2 electrode in order to remove th e surface decomposed layer of the PZT film. By this HNO3-treatment, the rem anent polarization was increased, and the squareness and symmetry of the po larization-voltage (P-V) hysteresis loop of the PZT film were improved. The P-V hysteresis loop of the 54-nm-thick HNO3-treated epitaxial PZT film was saturated at about 1.5 V. Although the coercive field E-c was increased by the HNO3-treatment, the coercive voltage was decreased by decreasing the f ilm thickness, It was also found that E-c can be lowered by improving the c rystalline quality of the PZT film.