微弧氧化SrTiO_3铁电薄膜的微观结构及性能

Microstructure and properties of SrTiO_3 ferroelectric thin film prepared by microarc oxidation

以0.2 mol/L Sr(OH)2+0.2 mol/L NaOH溶液为电解液,工艺参数分别设置为电流密度2 A/cm2、电流频率100 Hz、反应时间30 min及占空比85%,采用微弧氧化法在工业纯Ti板(99.5%)表面原位生长SrTiO3薄膜,并对薄膜的物相组成,元素分布情况及薄膜介电、铁电性能进行表征。结果表明:所得薄膜主要由四方相SrTiO3构成。薄膜介电常数随频率升高而降低,其在1 kHz条件下的介电常数为317。薄膜中除Sr、Ti、O元素外,还存在Na元素,且Na元素在薄膜与基体结合处出现富集,元素分布的微小波动可能是由微弧氧化孔洞造成。

Microarc oxidation was conducted by placing titanium plates as anode in 0. 2 mol /L strontium hydroxide and 0. 2 mol /L sodium hydroxide aqueous solution,with current density of 2 A /cm2,current frequency of 100 Hz,processing time of 30 min and duty ratio of85%. Phase composition,element distribution and ferroelectric properties of the SrTiO3film were investigated. The results show that the film is mainly composed of tetragonal strontium titanate phases and possess high dielectric constant of 317 at the frequency of 1 kHz. And it is demonstrated that with increasing of the frequencies,the dielectric constant increases. In addition to Sr,Ti and O,there is element of Na exist,and the enrichment of Na element appears near the substrate,also small fluctuations in the distribution of elements may be caused by micropore.