Electrical properties of zirconium-rich PZT thin films by RF magnetron sputtering

Zirconium (Zr)-rich lead zirconate titanate (PZT) thin films show the phase transition from a lower temperature rhombohedral ferroelectric (F-R(LT)) t o high temperature (F-R(HT)) phases. Zr-rich PZT thin films will be a candi date for sensor and memory applications, because large pyroelectric current s appear at this phase transition. In this study, highly [111]-oriented Zr- rich thin films with a thickness of 0.3 similar to 1 mu m were successfully grown on (111)Ir/SiO2/Si substrates by an RF magnetron sputtering using a multi-target which consisted of calcinated PbO and metal titanium pellets o n a Zr metal plate. The composition of the films could be controlled by adj usting the area ratio of PbO/Zr/Ti. The crystal structures of films were se nsitive to the substrate temperature. The pyroelectric coefficient of Zr/Ti =93.6/6.4 and 96/4 as-prepared PZT films showed a peak at 87 and 47 degrees C, respectively, which corresponded to the phase transition from F-R(LT) t o FR(HT) The Phase transition temperatures from F-R(HT) to P-C were also 22 4 and 215 degrees C for the Zr/Ti=93.6/6.4 and 96/4, respectively. The fati gue characteristic was also measured using double bipolar pulses. The PZT f ilms preserved an initial P-r value over switching cycle of 10(12).