Advanced morphological characterization of DC sputtered copper thin films

• Published in: Modern physics letters. B, Condensed matter physics, statistical physics, applied physics Vol. 38; no. 10
• Main Authors: Korpi, Alireza Grayeli, Rezaee, Sahar, Ahmadpourian, Azin, Ţălu, Ştefan, Jen, Tien-Chien
• Format: Journal Article
• Language: English
• Published: Singapore World Scientific Publishing Company 10.04.2024; World Scientific Publishing Co. Pte., Ltd
• Subjects: Algorithms; Atomic force microscopy; Copper; Density functions; Deposition; Fractal analysis; Fractal geometry; Fractals; Glass substrates; Height; Magnetron sputtering; Morphology; Power spectral density; Roughness; Spectral density function; Thin films; multifractal analyses; deposition time; fractal analysis; Copper thin films; sputtering; surface roughness
• ISSN: 0217-9849; 1793-6640
• DOI: 10.1142/S0217984924500532

In this paper, Cu thin films were successfully deposited on glass substrates using DC magnetron sputtering at varying deposition times. The deposition time was varied as 5, 9, 11 and 17 min. The obtained Cu thin films were analyzed for morphology and topography using atomic force microscopy (AFM). The size of the surface structures/grains was seen to evolve with deposition time. The conventional/statistical, fractal and multifractal analyses were carried out on AFM images using existing imaging algorithms. The arithmetic roughness and interface width parameters were seen to evolve with the sputtering time. The autocorrelation and height–height correlation functions revealed that the surfaces of all the Cu thin films exhibited self-affine character, but were not mounded properties. The fractal dimensions computed using box counting and power spectral density functions revealed that larger dimensions were associated with larger surface features. The lacunarity coefficients were too small indicating that the surfaces were generally deficient in porosity and other defects. The multifractal analyses revealed that spatial roughness does not exhibit linear relationship with the deposition time. The study reveals that surface evolution and nanoscale behavior is significantly influenced by the deposition time although a linear relationship is not established.