利用磁控溅射法,在Si(100)衬底上制备了不同厚度的非晶导电薄膜Ni-Al底电极,并采用直滴法、退火工艺和掩膜技术,首先制备了偏氟乙烯-三氟乙烯P(VDF-TrFE)共聚物铁电薄膜,并构架了Al/ P(VDF-TrFE)/Ni-Al/Si铁电电容器异质结.采用X线衍射仪(XRD)、铁电测试仪(Precision LC unit)等测试手段对薄膜的性能进行了表征.结果表明:Ni-Al薄膜厚度对偏氟乙烯-三氟乙烯共聚物薄膜的漏电流产生较大影响,当厚度为36 nm时,其漏电流密度达到2.09×10~(-5) A/cm~2;所构架的Al/ P(VDF-TrFE) /Ni-Al /Si电容器呈现2种漏电机理,在较低的电场范围内,电容器的导电机理为欧姆导电机理,在高电场下为界面肖特基导电机理.
Ni-Al films with different thicknesses used as the bottom electrode layers are prepared on Si(100) at room temperature by magnetron sputtering method, and P(VDF-TrFE) copolymer film is prepared by direct dripping method, which is followed by an annealing process to further obtain Al/ P(VDF-TrFE)/Ni-Al/Si ferroelectric capacitor heterostructures through a shadow mask. Various techniques, such as X-ray diffraction (XRD), ferroelectric tester (Precision LC unit) have been employed to characterize the microstructure and ferroelectric properties of the ferroelectric capacitors. It is found that thickness of Ni-Al film have a large effect on leakage current of P(VDF-TrFE) copolymer film. When the thickness of Ni-Al film is 36 nm, leakage current density of P(VDF-TrFE) copolymer film is 2.09×10~(-5) A/cm~2. Leakage current mechanism of the Al/ P(VDF-TrFE)/Ni-Al/Si ferroelectric capacitor is further investigated, it is found that Al/ P(VDF-TrFE)/Ni-Al/Si corresponds to Ohmic conduction behavior at low electric field and Schottky emission at higher electric field.
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