Microstructure Characterization And Electric Properties Of PLCT Ferroelectric Thin Films

PbTiO3-Based thin film has broad application prospects in pyroelectric detectors, dynanmic random access memory, non-volatile ferroelectric memories and micro-electro-mechanical systems. However, the PT-based ferroelectric thin films, especially used in practical devices, still have some obstacles, generally including maintaining the good electrical properties of buik materials, reducing maintaining the good electrical properties of bulk materials, reducing processing temperature, increasing fatigue resistance and lowing leakage current characteristics. In this paper, we use sol-gel technology to preparePb1-x-yLaxCayTi1-x/4O3thin film, and study microstructure characterization and electric properties of PLCT doping.Firstly, Pb1-x-yLaxCayTi1-x/4O3(x=0.2, y=0)(x=0.15, y=0.05)(x=0.1, y=0.1)(x=0.05,y=0.15)(x=0,y=0.2) thin films were prepared on Pt/TiO2/SiO2/Si substrates by sol-gel process, study effect of doping on the texture of films was investigated. the phase and the texture of the films were characterized using X-ray diffraction (XRD), the remnant polarization and fatigue resistance of the films were also measured. Secondly, The Pb0.8La0.1Ca0.1Ti0.975O3was deposited by sol-gel on Pt/TiO2/SiO2/Si substrates in the first, and then the Pb0.8Ca0.2TiO3was deposited on the Pb0.8La0.1Ca0.1Ti0.975O3thin film using magnetron sputtering, The thickness of Pb0.8La0.1Ca0.1Ti0.975O3was measured by X-ray diffraction (XRD) at low angles and its effect on the performance of Pb0.8Ca0.2TiO3films were also studied. The last, the surface morphology of the Pb0.8Ca0.2TiO3films were analyzed by AFM, and the leakage current of films were measured using ferroelectric tester.The results showed that, the PbTiO3-based ferroelectric thin film diffraction peak intensity obvious difference by doped Pb3+, Ca2+ion, the texture of films had effectively controlled. Lattice distortion was caused greatly and the (200) diffraction peaks shifted toward high angles. The remanent polarization increased because of the co-substitution of high valance and low valance to (x=0.1, y=0.1), which would decrease if the concentration of Ca2+continued increasing. So was the fatigue resistance of the films. The thickness of Pb0.8La0.1Ca0.1Ti0.975O3was14nm measured successfully by the X-ray scattering techniques at low angles. The Pb0.8La0.1Ca0.1Ti0.975O3films were crystallized completely by the RTA process at450℃through its XRD patterns. The thin film showed strong (100) peak, it indicated that the film was perovskite structure, It can ben found that the (100)-orientation of Pb0.8Ca0.2TiO3thin film was enhanced owing to the introduction of seed layer. At the same time, the surface morphology of Pb0.8Ca0.2TiO3thin film had been greatly improved and its leakage current also reduced effectively.