底电极原位退火与沉积温度对PZT薄膜性能影响研究

Influences of In-Situ Annealing and Deposition Temperature of Bottom Electrodes on Properties of PZT Films

采用磁控溅射工艺,在Pt/Ti底电极上沉积锆钛酸铅(PZT)薄膜,研究了原位退火温度与底电极沉积温度对溅射PZT薄膜结晶取向、微观结构、介电性能、铁电性能及疲劳性能的影响。X射线衍射(XRD)和扫描电子显微镜(SEM)分析结果表明,随着电极沉积温度升高,Pt晶粒尺寸增大,随着退火温度升高,PZT薄膜致密性变差。对室温制备的Pt/Ti底电极进行200℃原位退火30 min后,易于促进PZT薄膜沿(100)择优取向,而高温制备或经高温退火处理的Pt/Ti底电极更有利于PZT薄膜的(111)晶向生长。电学性能分析表明,室温制备的Pt/Ti底电极在经200℃原位退火30 min后,其PZT薄膜介电性能最优,同时展现较高的剩余极化强度和最小的矫顽场强,经历108次极化翻转后,初始极化下降仅为11%。

Lead zirconium titanate(PZT) films were deposited on Pt/Ti bottom electrode by magnetron sputtering process. The influences of in-situ annealing temperature and electrode deposition temperature on crystal orientation, microstructure, dielectric, ferroelectric, and fatigue characteristics of sputtered PZT films were studied. The results of X-ray diffraction(XRD) and scanning electron microscope(SEM) analysis show that as the electrode deposition temperature increases, the Pt crystal grain size increases, and as the annealing temperature increases, the PZT film compactness becomes worse. The Pt/Ti bottom electrode prepared at room temperature after in-situ annealed in 200 ℃ for 30 min can easily promote the(100) orientation of the PZT film, while the Pt/Ti bottom electrode prepared or annealed at high temperature is more conducive to the(111) orientation. The best dielectric property is obtained in the PZT film according to electrical tests, in which the Pt/Ti bottom electrode is prepared at room temperature and in-situ annealed in 200 ℃ for 30 min. And the PZT film exhibits high residual polarization strength and minimum coercive field strength. After 10~8 times polarization inversions, the initial polarization of the film drop is only 11%.