组分和应力不均匀分布对薄膜铁电性的影响

The Effects of Non-uniform Distributions of Stress and Composition on Ferroelectric Thin Films

采用组合靶射频溅射的方法、制备后慢速降温的途径在（１１１）Ｓｉ基板上制备出了成膜较好的 ＰｂＴｉＯ３薄膜。通过测试分析发现在薄膜中形成了一个缓解应力的过渡层，薄膜中的Ｐｂ、Ｔｉ组分比沿着薄膜生长的方向成非线性增长，并在薄膜表面形成一个富Ｐｂ层，薄膜的Ｃ－Ｖ特性曲线中存在负方向的位移和畸变。结合实验结果对薄膜的生长机理进行了探讨，并且对薄膜中的应力和不均匀分布的组分对薄膜铁电特性的影响进行了理论上的分析，而且与实验取得了一致的结果。

PbTiO3 thin films with pervoskite-type microstructures were synthesized directly on the (111 ) Si substrate using a rf-magnetron sputtering system with a composite target at a low substrate cooling rate. The films were investigated with various methods,and the results shown that a transition layer was formed near the substrate surface in order to relax the stress between film and substrate. The non-uniform distribution of compositions was also found,and negative shift and two humps existed in the C-V curves. The mechanism of the film growth is discussed,and a theoretic explanation is proposed and they met the experiment results quite well.