Size effect on the mechanical behavior of Al/Si multilayers deposited on Kapton substrate

Abstract

The mechanical properties of multilayers with individual layer thickness in the nanometers range have attracted an increased attention due to the important implication on the reliability of microelectronic devices. In this work, Al/Si multilayers with different individual layer thickness t (25, 100, 250 nm) but with the same total thickness (1.0 µm), were fabricated by magnetron sputtering onto Kapton substrates, and then were studied by tensile testing with maximal strain of emax = 10 %. It is found the thinner the individual layer is, it is more difficult to generate the plastic shear deformation. And the tensile strength increases with decreasing layer thickness. Many buckling damages appeared on the surface of Al/Si multilayer under the compressive stress vertical to the tensile direction. The buckling becomes more and more absent when the individual layer thickness decreases from sub-micron scale to nanometer scale.