Microstructure and ferroelectric properties of Bi 3.2Y 0.8Ti 3O 12 thin films prepared by sol–gel method

Abstract

Yttrium-substituted bismuth titanate (Bi 3.2Y 0.8Ti 3O 12, BYT) thin films were successfully deposited on Pt(1 1 1)/Ti/SiO 2/Si(1 0 0) substrates by spin coating with a sol–gel technology and rapid thermal annealing. The effects of annealing temperature (500–800 °C) on microstructure and electrical properties of thin films were investigated. X-ray diffraction analysis shows that the BYT thin films have a bismuth-layered perovskite structure with preferred (1 1 7) orientation. The intensities of (1 1 7) peaks increases with increasing annealing temperature. With the increase of annealing temperature from 500 to 800 °C, the grain size of BYT thin films increases. The highly (1 1 7)-oriented BYT thin films exhibit a high-remnant polarization (2 P r) of 58 μC/cm 2 and a low-coercive field (2 E c) of 116 kV/cm, fatigue free characteristics up to >10 8 switching cycles. The leakage current density ( J) were 4.38×10 −8 A/cm 2 at 200 kV/cm. These results indicate that the highly (1 1 7)-oriented BYT thin film is useful in nonvolatile ferroelectric random access memory applications.