Effects of annealing temperature and pressure of vacuum infiltration on the electrical properties of Pb(Zr_(0.52)Ti_(0.48))O_3 thick films prepared via a modified sol-gel method

摘要

In this study, piezoelectric Pb(Zr0.52Ti0.48)O-3 (Lead Zirconate Titanate PZT) thick films were fabricated on Pt-coated Si substrates via a modified sol-gel method. The method involved a uniform dispersion of PZT-based powders in sol-gel solution. This modification increased single coating thickness, reduced coating time, and improved electrical characteristics. We found that the dielectric, ferroelectric, and piezoelectric properties of the films depended on microstructure and crystallinity. Diagram models were proposed to explain these results. The size of grains that filled the surface pores of the films increased with annealing temperature. Surface roughness decreased with grain size up to a point. However, excessively large grains increased surface roughness. A sec-ondary phase formed at 750 degrees C. Excessively high pressure of vacuum infiltration caused the sol-gel solution to evaporate and accumulate on the film surface, affecting microstructure and crystallinity. The optimized films, obtained with an annealing temperature of 700 degrees C and a vacuum pressure of 0.073 MPa (according to the pumping time), had a dielectric constant of 1542 (at 1 kHz), a dielectric loss of 0.029 (at 1 kHz), a remanent polarization P-r of 39.8 mu C/cm(2) (at 350 kV/cm), and an effective piezoelectric coefficient d(33 ,f) of 93.6 pm/V.