金属有机化学气相沉积法制备钛酸铅铁电薄膜

PREPARATION AND CHARACTERIZATION OF PbTiO 3 THIN FILMS BY METALORGANIC CHEMICAL VAPOR DEPOSITION

利用低压ＭＯＣＶＤ工艺分别在（００１）取向的ＬａＡｌＯ３，ＳｒＴｉＯ３和重掺杂硅单晶衬底上制备ＰｂＴｉＯ３铁电薄膜，并通过Ｘ射线衍射谱对薄膜的微结构进行分析．Ｘ射线θ－２θ扫描显示硅衬底上得到了ＰｂＴｉＯ３多晶薄膜，另两种衬底上得到了择优取向的ＰｂＴｉＯ３薄膜．ＬａＡｌＯ３衬底上的ＰｂＴｉＯ３薄膜有ａ和ｃ两个取向，也就是薄膜中存在着９０°畴结构，而生长在ＳｒＴｉＯ３衬底上的ＰｂＴｉＯ３薄膜中只存在ｃ方向的择优取向．由于薄膜的尺度效应，发现ｃ轴晶格常数与块材相比均缩短．Ｘ射线的φ扫描验证了后两类薄膜的外延特性，利用同步辐射的高强度和高能量分辨率用摇摆曲线方法研究了这两种外延薄膜的品质，进一步证明了ＳｒＴｉＯ３衬底上的ＰｂＴｉＯ３薄膜的单畴特性．利用重掺杂的硅衬底作底电极。

PbTiO 3 thin films were deposited on (001) redoping n Si,(001)LaAlO 3 and (001) SrTiO 3 substrates by low pressure MOCVD technique,XRD θ 2θ scan shows that the film on Si substrate has a polycrystalline structure,while the other two films have preferential orientations and their epitaxial nature was confirmed by the X ray φ scan,rocking curves of the two epitaxial thin films were taken at BSRF using the synchrotron radiation. The film on LaAlO 3 substrate has an a,c domain coexisting structure,and the film on SrTiO 3 substrate only has a c orientation. All the films exhibit a c axis shortening compare with the bulk material,and the reason can be attributed to the size effect and surface influence. The ferroelectric properties of the polycrystalline thin films were investigated using the redoping Si substrate as bottom electrode directly,and the PbTiO 3 thin film shows a perfect hysteresis loop.