Microstructure and Properties of Sol-Gel PZT Thin Films with Buffer Layers

摘要

Smart hetero-structures Pb(Zr,Ti)O_3(PZT)/NiTi multilayer thin films were fabricated on Si (100) substrates. Sol-gel techniques were used to prepare PZT layers. PbTiO_3 and TiO_2 buffer layers were introduced between PZT and NiTi thin films to improve the crystallity and dielectric properties of multi-layers. Results of experiments showed PZT/PT/TiO_2/NiTi/Si(100) possess perovskite structure and better comprehensive electrical properties after annealing at 550°C for 30 min. Amorphous sputtering NiTi thin films had been crystallised to high temperature B_2 phase. The leak current density is 4.62 x 10~(-9) A/cm~2 at the drive field of 15 kV/cm. The dielectric constant E and dissipation factor are 413 and 0.013 at 1 KHz respectively. A remnant polarization of 0.52 uc/cm~2 and coercive field of 21.2 and -20.6 kV/cm were obtained for the 0.8 um thick film. AFM images of different multilayer structures have obviously different grain morphology.