Dynamics of Surface Morphology of Cu Film Under the Influence of Heat: An Experimental and Theoretical Study

Abstract

The evolution of surface morphology and formation of oxides is meticulously studied in annealed copper thin films in oxygen environment at various temperature using experimental results and Higuchi's algorithm. Initially, thin film of copper is deposited using thermal evaporation system having thickness of 27 nm and subsequently oxidized by annealing in temperatures range of 150 °C to 350 °C with a temperature interval of 50 °C in oxygen environment for one hour. The 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 by rising in the temperature from 250 to 350 °C. The optical band gap of annealed copper films at different temperatures is calculated by Tauc's plot and it indicates the formation of Cupreous and Cupric oxide. A clear morphological variation is seen in AFM images of the surface of films. Additionally, Higuchi's algorithm for surface morphology is performed to observe the change in surface morphology under the effect of temperature variation in oxygen environment by various parameters e.g. interface width (w), Hurst exponent (H) and fractal dimension (Df).