Surface characterization of Cu/Ti thin films by fractal analysis

摘要

Copper/Titanium (Cu/Ti) metallic thin bilayer films, xCu/10nmTi/Si and xCu/30nmTi/Si (x=10nm, 20nm, 30nm, respectively), were deposited by DC magnetron sputtering technique. An atomic force microscopy (AFM) was used to measure the surface morphology. The height-height correlation function, described by the surface parameter of roughness exponent α, together with the evolutions of the familiar parameters of roughness w and autocorrelation length ξ, was used to describe the surface quantitatively. The fractal dimension Dƒ of the surface was calculated. The values of Dƒ reduce with the Cu film thickness increasing for the samples of Cu/10nmTi/Si and increase for the samples of Cu/30nmTi/Si. The surface will be rougher for the samples of Cu/10nmTi/Si as the Cu film increasing from 10nm to 30nm and become smoother for the samples of Cu/10nmTi/Si.