Ferroelectric La-Sr-Co-O/Pb-Zr-Ti-O/La-Sr-Co-O heterostructures on silicon: reliability testing
We report results of pulsed electrical testing of ferroelectric Pb0.9La0.1Zr0.2Ti0.8O3 thin film capacitors with symmetrical La-Sr-Co-O top and bottom electrodes at room temperatures and at 100°C. They have been grown on (001) Si with a Yttria stabilized zirconia (YSZ) buffer layer. A layered perovskite 'template' layer (200-300A thick), grown between the YSZ buffer layer and bottom La-Sr-Co-O electrode, is critical for obtaining the required orientation of the subsequent layers. When compared to the capacitors grown with Y-Ba-Cu-O (YBCO) top and bottom electrodes, these structures posses two advantages : (1) the growth temperatures are lower by 60-150DGRC; (ii) the capacitors show a large remnant polarization, AP, (ΔP = switched polarization- non-switched polarization), 25-30 μC/cm2, for an applied voltage of only 2V (applied field of 70 kV/cm). The fatigue, retention and aging characteristics of these new structures are excellent at both room temperature and at 100°C.