材料期刊网

采用磁控溅射技术在单晶硅片上制备了恒定调制周期(λ =25,40 nm)、不同调制比(η=0.1～ 10.5)的Cu/Zr纳米多层膜.分别通过透射电子显微镜研究分析Cu/Zr多层膜的微观结构,通过四探针测量法系统研究Cu/Zr多层膜电阻率的尺寸效应.微观结构分析表明:Cu/Zr多层膜呈现周期性层状结构,层界面清晰.调制周期与调制比均显著影响Cu/Zr多层膜的电阻率(p).相同调制周期下,η大于临界调制比(ηc≈1)时,ρ几乎与η无关;而η小于此临界调制比(ηc≈1)时,p随η减小急剧增大.利用Fuchs-Sondheimer和Mayadas-Shatzkes(FS-MS)传输模型可以对实验数据进行很好的拟合,拟合结果表明:当η＞ηc时,晶界散射和界面散射协同作用是Cu/Zr多层膜电阻率变化的主控机制;当η＜ηc时,晶界散射成为多层膜电阻率变化的主导因素.

The Cu/Zr nanostructured metallic multilayers with constant modulation periods (λ =25,40 nm),covering a wide range of modulation ratio ηspanning from 0.1 to 10.5,were deposited on the Si substrate by DC magnetron sputtering.By using the transmission electron microscopy and the four point probe method,the microstructure and size effects on the electrical resistivity (p) of Cu/Zr nanostructured multilayers were systematically investigated.It is revealed from the microstructural analysis that the modulation structure of Cu/Zr metallic muhilayers is clear and the interfaces are distinguishable.Both the modulation periods λ and the modulation ratio ηsignificantly influence the resistivity p of Cu/Zr multilayers.The smaller is the modulation periods λ,the greater is the resistivity p.Above a critical modulation ratio (ηc ≈ 1) the resistivity is independent on the modulation ratio,below which the resistivity sharply increases with decreasing the modulation ratio.The combined Fuchs-Sondheimer and Mayadas-Shatzkes (FS-MS) model can be used to fit the experimental data well.It is found that when η＞ ηc,the resistivity of Cu/Zr multilayers is determined by the cooperative effect of grain boundary scattering and interface scattering;When η＜ ηc,the resistivity of Cu/Zr multilayers is mainly determined by grain boundary scattering.