Multifractal spectra of atomic force microscope images of amorphous electroless Ni–Cu–P alloy

The surface topographies of Si/TiN/Pd substrate and amorphous electroless Ni–13.1 wt.% Cu–9.3 wt.% P alloy deposited for various times were measured by atomic force microscope (AFM). Multifractal spectra f(α) show that the longer the deposition time, the wider the spectrum, and the larger the Δf (Δf=f(αmin)−f(αmax)). It is apparent that the nonuniformity of the height distribution increases with the increasing deposition time, and the nodules of Ni–Cu–P alloy grow in both horizontal and vertical way. These results show that the AFM images can be characterized by the multifractal spectra.