Abstract: (345 Views)
Series of cobalt (Co) thin films with various thicknesses ranging from 50 to 400 nm have been fabricated using thermal heating under vacuum. We explore the impact of the thickness layer on the structural and morphological properties of the films. X-Ray diffractions and atomic force microscopy tools have been used to carry out the structural and the morphological properties of these films. The films are principally c-axis oriented, polycrystalline and with <0001> texture. The crystallites sizes have been found to range from 18.40 to 79.46 nm, and they increase with increasing thickness. The ratio c/a value indicates that Co films are subject to a tensile stress, probably because of the way the film grows. The microstrain is positive and ranges from 1.53 to 3.56%. Atomic force microscopy observations indicate the formation of crystallites according to the Stranski-Krastanov mode. The films topographical surfaces are very smooth, the average root mean square roughness ranging from 0.2 to 1.5 nm.
Keywords: Co; Thin films; XRD; Crystallite size; AFM.
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Cobalt thin films prepared by evaporation under vacuum.
The crystallite size and cell parameters increase with thickness.
c/a ratio greater than the bulk value.
The films are under a tensile stress.
c/a ratio increases with crystallite size.
The films are very smooth, the rms roughness range being 0.2-1.5 nm.