Multifractal spectra of atomic force microscope images of lanthanum oxide thin films deposited by electron beam evaporation

The concept of fractal geometry has been widely used in describing structures and processes in experimental systems. In this letter, La2O3 thin films were deposited by the electron beam evaporation on a silicon substrate and then were annealed at 900 °C for various times. The surface characteristics of the films were investigated by means of an atomic force microscope method. The relationship between the time of the rapid thermal annealing process and the characteristics of the resulting surface morphology was examined. Multifractal spectra f(a  ) show that the effect of annealing time on the width of spectrum and ΔfΔf is apparent. The various multifractal spectra indicate that the surface roughness decreases firstly and then increases with increase in the annealing time. These results show that the atomic force microscope images can be characterized by the multifractal spectra.