Influence of heat on dynamics of surface morphology of Cu film: An experimental and theoretical perspective

Abstract

The evolution of surface morphology and formation of oxides are investigated in annealed copper thin films in oxygen environment at various temperature using experimental results and Higuchi's algorithm. Initially, thin film of copper of thickness 27 nm is deposited using thermal evaporation technique and subsequently oxidized by annealing in a temperature range of 150 °C–350 °C with a temperature interval of 50 °C in oxygen environment for 1 h. Studies of morphological, structural and optical properties of samples are performed by atomic force microscopy (AFM), X-Ray diffraction (XRD) and UV-VIS spectroscopy respectively. XRD results reveal that Cu2O phase changes completely to CuO phase when temperature is raised from 250 to 350 °C. The optical band gap of annealed copper films at different temperatures is calculated by Tauc's plot and these indicate the formation of Cupreous and Cupric oxide. A clear morphological variation is seen in AFM images of the film surfaces. Changes in surface morphology under the effect of temperature variation in oxygen environment were explored through various parameters e.g. interface width (w), Hurst exponent (H) and fractal dimension (Df) determined by Higuchi's algorithm.