Influence of Sputtering Gas on Morphological and Optical Properties of Magnesium Films

The influence of sputtering gas (He & Ar) on the structural properties of Mg thin films has been investigated. The optical property (reflectance) that results from the growth of films at varying substrate temperatures (Tsub) was also studied. The deposited films were characterized by using X-ray diffraction (XRD), field emission scaning electron microscopy (FE-SEM), atomic force microscopy (AFM) and UV-Vis-NIR spectrophotometer. The smaller crystallite size and lower deposition rate were observed in the presence of Helium atmosphere compared to Argon. Morphology of the films shows 2D hexagonal geometry of grains in the deposition temperature range (Tsub≈50-150°C) in both the sputtering gases. The surface roughness of the polycrystalline films were found to increase with increase in the deposition temperature of both ambient gases. Optical reflectance of Mg films was measured in near infrared region and larger reflectance was observed from Mg films sputtered in He atmosphere compared to that in argon.