磁控溅射Cu/Mo纳米多层膜的结构与性能

用磁控溅射法在单晶硅和聚酰亚胺衬底上制备了恒定调制比(η=1)、调制周期λ=10～ 100 nm的Cu/Mo纳米多层膜,运用XRD,HRTEM,EDX,AFM,单轴拉伸系统、显微硬度仪和电阻仪对多层膜的微观结构、表面形貌和力学及电学性能进行了研究.结果表明,Cu/Mo多层膜中的Cu层和Mo层分别具有Cu( 111)和Mo(110)择优取向,Cu层呈柱状纳米晶、Mo层为极细纳米晶结构,Cu/Mo层间界面处存在一定厚度的扩散混合层.Cu/Mo多层膜的结构和性能受到调制周期和Cu层厚度的显著影响.在调制比η=1的条件下,随着调制周期的增加,软相Cu层厚度增大,Cu/Mo多层膜总体的屈服强度和显微硬度明显下降,裂纹萌生临界应变εc和电导率则显著上升.主要原因在于,随Cu层厚度的增加,Cu晶粒尺寸增大,Cu层内晶界密度降低,使Cu层的位错运动阻力减小、塑性变形能力增强,Cu层内电子散射效应减弱.同时当Cu/Mo多层膜总厚度恒定时,多层膜中Cu层和Mo层的层间界面数量亦随Cu层厚度的增加而减少,减弱了层间界面的电子散射效应,从而使多层膜电导率得以提高.

Structure and Properties of Cu/Mo Nanostructure Multilayer Deposited by Magnetron Sputtering

Silicon-based and polyimide-based Cu/Mo nanostructure multilayer with constant modulation ratio(η=1) and modulation period(λ=10～100 nm) were prepared by magnetron sputtering.The microstructure,surface topography,mechanical and electrical properties of Cu/Mo multilayer were investigated by XRD,HRTEM,EDX,AFM,uniaxial tensile system,microhardness instrument and resistivity meter.The results showed that Cu and Mo layers of Cu/Mo multilayer were of Cu(111) and Mo(110) texture,respectively.Cu layer possessed columnar nanocrystalline while and Mo layer showed ultra-fine nanocrystalline structure.On the interface of Cu/Mo layers,there was diffusion intermixing layer with definite thickness.The structure and properties of Cu/Mo multilayer were influenced by modulation period and the thickness of Cu layer significantly.The thickness of ductile Cu layer increased with the increasing modulation period(λ) under the condition of modulation ratio η=1,thus,the overall yield strength and microhardness of Cu/Mo multilayer were dramatically reduced,the critical strain of crack initiation εc and electrical conductivity were improved obviously.The increased grain size of Cu layer and the decreased density of grain boundary with the increasing thickness of Cu layer reduced the resistance of dislocation movement,enhanced the plastic deformation capacity and reduced the interlayer electron scattering effects.Meanwhile,the amount of the interface between Cu layer and Mo layer in multilayer decreased with the increasing thickness of Cu layer when the total thickness of the Cu/Mo multilayer was constant,resulted in the electron scattering effects of interface layer weakened,further to improve the electrical conductivity of multilayer.