Comparison of the ferroelectricity for 70-80 nm thick Pb(Zr,Ti)O ₃ films deposited on (111)Ir bottom electrodes at different temperatures by MOCVD

70-80 nm-thick Pb(Zr,Ti)O₃ (PZT) films were deposited on (111)Ir/TiO₂/SiO₂/Si substrates at 415 and 540°C by metalorganic chemical vapor deposition (MOCVD). The remanent polarization (P_r) value showed 22 μC/cm² at an applied voltage of 3 V, even for the film deposited at 415°C. However, this value was almost 40% of that for the film deposited at the higher temperature. P_r value was enhanced up to 40 μC/cm² and the squareness of the polarization-electric field (P-E) hysteresis loop was also improved by the post-annealing at 500°C, even though a noticeable change was not detected on the x-ray diffraction pattern. Moreover, both of the P, and coercive field (E_c) values of the film annealed at 500°C after 415°C-deposition were almost saturated belosv 2 V, as same as the as-deposited films at 540°C.