Enhanced fatigue characteristics of sol–gel derived PZT thin films

Pb(Zr,Ti)O3 (PZT) thin films with Zr/Ti ratio of 52:48 were deposited on Pt/Ti/SiO2/Si substrates using the sol–gel method. Since the conditions of heat-treatment play a great role in film growth, post-annealing processes were conducted under different environments. After standard processing, films were annealed at 600 °C in three different atmosphere—air, O2 and a two-step process conducted in air for 30 min and then in O2 ambient, all done for 10 min. Through electron microscopy and X-ray diffraction, we found that all films were crack-free and highly (1 1 1) oriented. Hysteresis measurements showed a generally large polarization value. The fatigue properties differ drastically for all processes, showing an abnormal behaviour near the end of the measurement. The hysteresis loops before and after 1 × 1010 switching cycles have been slightly changed in both shape and magnitude. Such abnormality and fatigue-free property is an unusual result for PZT films prepared on conventional Pt/Ti/SiO2/Si substrates.