Influence of Fabrication Parameters on Crystallization, Microstructure, Surface Composition, and Optical Behavior of MgO Thin Films Deposited by rf Magnetron Sputtering

In this work MgO thin films have been grown onto common glass substrates by magnetron rf sputtering from a MgO (99.99%) target with dimensions of 4″×¼″. Basically, we found the optimum conditions for deposition such as working pressure (7×10^?3 mbar), the power applied to the target (400 W) and the flow of Ar (20 sccm). The films have been characterized by X-ray diffraction (XRD) at a grazing angle at θ–2θ configuration, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and transmittance studies. The XRD results show that to reproduce the polycrystalline phase of the target, there is a power threshold of 250 W. AFM results indicate that the films present average roughness of the 200 Å and grain size of 1100 Å. XPS shows a surface composition of the films most external 5 nm, indicating the presence of MgO and Mg(OH)₂. The optical characterization indicates that the films have a high absorption coefficient for wavelengths below 310 nm, and between 450 to 850 nm they showed a transmittance average of 90%.