Effect of High-Pressure Oxygen Annealing on Bi2SiO5-Added Ferroelectric Thin Films

Abstract

The crystallization temperature of typical ferroelectric films such as PbZr1-XTiXO3 (PZT), SrBi2Ta2O9 (SBT), and (Bi,La)4Ti3O12 (BLT) was found to decrease by 150 to 200°C in a chemical solution deposition method by adding Bi2SiO5 (BSO) in the sol-gel solutions. It was also found that the ferroelectric and insulating characteristics of the BSO-added films were significantly improved by annealing in high-pressure oxygen up to 9.9 atms. Three-orders-of-magnitude improvement of the leakage current density was observed in BSO-added BLT films after annealing at 9.9 atms, while pronounced increase of the saturation polarization level was observed in BSO-added SBT and PZT films. From cross-sectional transmission electron microscopy (TEM) observations, the origin of the improved characteristics was speculated to be the structural change of the films.