Self-affine nature of thin film surface

Variation–correlation function VCF., a fractal model for quantitative analysis on 3D surface, has been applied to the description of Co-based thin film surfaces imaged by atomic force microscope AFM.. The results of two group experiments on the thin films have implied that the change in fractal dimension Dcor is in accordance with that in surface energy Esv of the thin films but height roughness Ra and Rms are not. A theoretical equation has been developed to demonstrate the relationship between fractal dimension Dcor and surface energy Esv. This equation shows that Dcor can be interpreted as a parameter of surface energy in thin film growth, and thus the thin film surfaces have fractal nature. This equation also successfully explains the phenomenon of fractal dimension decrease for the thin films during annealing. This study shows that VCF method provides a reasonable parameter for quantitative description of irregularity of thin film surfaces. q2000 Elsevier Science B.V. All rights reserved