Low-temperature preparation of sputter-deposited Pb(Zr_0.52Ti_0.48)O₃ thin films through high oxygen-pressure annealing

This study examined the effect of high oxygen-pressure processing (HOPP) annealing on sputtered Pb(Zr_xTi_1-x)O₃ (PZT) thin films. Three hundred nanometer-thick PZT(52/48) thin films were sputter-deposited on the LNO-coated silicon substrates at a substrate temperature of 200 °C. The as-sputtered PZT(52/48) films were amorphous. On the other hand, after HOPP processing at 400 °C with applying oxygen pressures of 2, 4, 6, and 8 MPa, respectively, all the PZT thin films transformed to a high (h 0 0)-oriented perovskite phase. The diffraction intensity of the (h 0 0) peaks increased with increasing oxygen pressure of the HOPP process, indicating better crystallinity. The surface morphology of the PZT thin film after HOPP showed unusual grain shapes compared to the round-shape observed on the conventionally fabricated films. The low-temperature crystallization of HOPP process is associated with a decrease in the nucleation barrier for perovskite phase formation with a high oxygen pressure. The electrical measurements, such as the P-V, C-V, and ε(ω), revealed good ferroelectric properties after HOPP. Better ferroelectric properties of the PZT thin films were obtained by further increasing the oxygen pressure during HOPP. This low-temperature HOPP is compatible with existing silicon-based technology, by incorporating sputtering and low-temperature annealing.