Multifractal analysis for Cu/Ti bilayer thin films

Two bilayer thin films with different stacking sequences, Cu/Ti/Si and Ti/Cu/Si, were deposited by DC magnetron sputtering technique. X-ray diffraction technique was used to measure the crystallization structures, and scanning electron microscopy and atomic force microscopy were used to measured surface morphology. The multifractal spectra f(α)-α was used to characterize the surface morphology. The result of |q|_max ≤ 53 is obtained by multifractal analysis. The shape of the multifractal spectra f(α) - α is hook-like for Cu/Ti/Si and bell jar-like for Ti/Cu/Si. The spectrum width Δα = α_max - α_min and Δf(=f(α_min) - f(α_max)) of the multifractal spectra is able to quantitatively analyze the growth and surface roughness of the Cu/Ti bilayer thin films. The surface of Ti/Cu/Si thin film is more uniform and smoother than the film of Cu/Ti/Si.