Power spectral density analysis to investigate morphology of Ni films

Abstract

Ni thin films grown by thermal evaporation and sputtering under different deposition conditions are characterised by structural and morphological properties using X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. XRD results suggested the growth of polycrystalline face-centred cubic Ni phase for all the samples. Morphological characteristics of the films were compared by analysing AFM data for root mean square roughness, height–height correlation function and power spectral density (PSD) measurements. Applying fractal and k-correlation fitting models to the PSD data, different morphological parameters are quantified. The study suggested that Ni films grown at higher substrate temperature (∼150 °C) by thermal evaporation and at low Ar pressure (∼0.2 Pa) by sputtering techniques yielded films of small surface roughness with a Brownian fractal self-affine surface.