Preparation and characteristics of PLZT (8/65/35) thin films by sol-gel method

Abstract

Pb,La)(Zr,Ti)O 3 is a ferroelectric material which has excellent pyroelectric, dielectric and ferroelectric properties, and has a wide application prospect in the field of microelectronics and integrated circuit. A variety of techniques have been used for the deposition of ferroelectric thin films, among the processes, the sol-gel method has its advantages. In this study, the pyroelectric lead lanthanum zirconnate titanate (PLZT) (8/65/35) thin films were prepared on Pt (111)/Ti/SiO 2 /Si (100) substrates using sol-gel method and their characteristics were analyzed. The orientation and structural properties of the PLZT films were measured by X-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. It was found that PbTiO 3 (PT) can promote the crystallinity of PLZT thin films. According to the results of the SEM, under the 700°C holding temperature, the lead content of PLZT films decreased with the increment of holding time. The ferroelectric hystersis loop, pyroelectric coefficient and dielectric constant were also measured. The electrical properties of the films were optimized by rapid thermal process (RTP) at 700°C. Ferroelectric hysteresis loop of PLZT thin film with PT seed layer was tested at the triangular wave voltage of 50V. The results showed that the remanent polarization (Pr) was 25.7 μC/cm 2 and the coercive strength (Ec) was 68 kV/cm. At 1 kHz, dielectric constant (ε r ) of 951 and dielectric loss (tanδ) of 0.048 were obtained, respectively. The pyroelectric coefficient was 1125μC/m 2 K. The results demonstrated that PLZT thin films could be prepared by sol-gel method and had good ferroelectric, dielectric and pyroelectric properties.