Aluminum-copper bilayers thin films deposited at room temperature by RF magnetron sputtering

Abstract

In this work, the effects of room temperature deposition on the structural properties of Al-Cu bilayers thin films were investigated. The bilayers were sputter deposited by RF magnetron sputtering on Si {100} wafers without substrate heating. The thickness of each layer is approximately 500 nm thick. Characterization were performed with grazing incidence X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) with chemical analysis by energy dispersive X-ray (EDX) and atomic force microscope (AFM). From deposition, polycrystalline Al and Cu thin films with {111} preferred orientation were grown on the surface of the substrate. The bilayers is nanocrystalline, having very fine crystallites size of less than 20 nm. With minimal microstrain influence, each layer shows different morphologies between the columnar and non columnar structure. AFM analysis revealed that the bilayers top surface exhibits higher surface roughness (Ra = 20 nm) due to low adatoms surface mobility during deposition