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用改进的溶胶-凝胶法(sol-gel)在Pt/Ti/SiO2/Si(S)上制备了各层Y掺杂浓度分别为0.5%/0.6%/0.7%/0.8%/0.9%/1%的上梯度掺杂和1%/0.9%/0.8%/0.7%/0.6%/0.5%下梯度掺杂的Ba0.6Sr0.4TiO3薄膜。X射线衍射(XRD)表明,各薄膜主要沿(110)晶面生长,均为立方钙钛矿结构。相比均匀掺杂薄膜,梯度掺杂薄膜表现出较好的相结构衍射强度及晶化,上梯度薄膜更为显著。原子力显微镜(AFM)表明,梯度掺杂使薄膜的表面形貌得到极大改善,上梯度比下梯度薄膜具有更加光滑致密的表面相貌和更小的表面粗糙度。电压-电容曲线表明,上梯度薄膜介电性能得到明显提高,在零偏压下的电容为28.5pF(介电常数190)、介电损耗为1.63%及40V下的调谐率为52.3%,优质因子为32。
The Y doping concentrations of each layer were prepared on Pt / Ti / SiO2 / Si (S) by sol-gel method with 0.5% / 0.6% / 0.7% / 0.8% / 0.9% 1% gradient-doped Ba0.6Sr0.4TiO3 film and 1% / 0.9% / 0.8% / 0.7% / 0.6% / 0.5%. X-ray diffraction (XRD) shows that the films mainly grow along the (110) plane and are cubic perovskite structures. Gradient doped films showed better phase structure diffraction intensity and crystallization, and the gradient films were more pronounced compared with those of uniform doping films. Atomic force microscopy (AFM) showed that the graded doping greatly improved the surface morphology of the films, the gradient of the graded films was smoother and more dense than the graded films and the surface roughness was smaller. The voltage-capacitance curve shows that the dielectric properties of the graded films are obviously improved. The capacitance at zero bias is 28.5pF (dielectric constant 190), the dielectric loss is 1.63% and the tuning rate at 40V is 52.3% The factor is 32.