低温热氧化法制备Bi_2Mo_3O_(12)介质薄膜

Bi_2Mo_3O_(12) Dielectric Thin Films Fabricated by Thermal Oxidation of the Sputtered Bi/Mo Films at Ultra-low Temperature

通过直流磁控溅射法在Si/Si O_2/Pt基片表面沉积摩尔比为2∶3的Bi/Mo多层薄膜。系统研究了热氧化温度对上述薄膜的物相组成、微观形貌、介电性能的影响。X-射线衍射(XRD)数据表明,420~480℃可热氧化形成介质薄膜。420℃氧化,薄膜的物相为Bi_2O_3、Mo O_3、Bi_2Mo O_6和Bi_2Mo_3O_(12);450℃和480℃氧化,薄膜的主相均为Bi_2Mo_3O_(12),另有少量Bi_2Mo O_6存在。扫描电镜(SEM)观察结果显示,薄膜在450℃即已致密、均匀。介电性能测试结果显示,480℃氧化的介质薄膜,具有较优的介电性能:1 k Hz测量,介电常数约15.6,介电损耗约0.65%;5.55 k V/mm电场强度下,漏电流密度约3.4×10^(-7) A/mm^2。考虑到Bi/Mo薄膜极低的成膜温度(480℃)及直流磁控溅射Bi/Mo金属薄膜较大的沉积速率(92 nm/min),直流磁控溅射Bi/Mo金属薄膜,然后热氧化成Bi_2Mo_3O_(12)介质薄膜,在工业上具有应用价值,有望应用于嵌入式薄膜电容器的制备。

Bi/Mo multilayer thin films with molar ration 2∶3 are deposited on Si/Si O2/Pt substrates by a direct current magnetron sputtering.Effect of annealed temperature on the microscopic structure,dielectric and electrical properties of the as-sputtered films have been investigated systematically.X-ray diffraction data show that the films annealed from 450℃to 480℃are a diphase mixture,Bi2Mo3O（12） principal phase with some Bi2Mo O6 as secondary phase.Scanning electron microscope observation indicates that the films annealed from 450℃to480℃are dense and uniform.The films annealed at 480℃exhibit optimal dielectric and electrical properties with dielectric constant about 15.6,dielectric loss about 0.65%at 1 k Hz,and leakage current density of 3.4×10-7A/mm2 at an electric field of 5.55 k V/mm.Considering that the densification temperature（480℃）is ultra low and the sputtering deposition rate（92 nm/min）is much high,we believe that thermal oxidation of the sputtered Bi/Mo films is a valuable technique for fabrication of Bi2Mo3O（12） ceramic thin film embedded-capacitors.