Annealing Effect on the Contact Angle, Surface Energy, Electric Property, and Nanomechanical Characteristics of Co40Fe40W20 Thin Films

Abstract

This study investigated Co40Fe40W20 single-layer thin films according to their corresponding structure, grain size, contact angle, and surface energy characteristics. Co40Fe40W20 alloy thin films of different thicknesses, ranging from 10 to 50 nm, were sputtered on Si(100) substrates by DC magnetron sputtering. The thin films were annealed under three conditions: as-deposited, 250 °C, and 350 °C temperatures, respectively. The Scherrer equation was applied to calculate the grain size of Co40Fe40W20 thin films. The results show that the grain size of CoFe(110) increased simultaneously with the increase of post-annealing temperature, suggesting that the crystallinity of Co40Fe40W20 thin films increased with the post-annealing temperature. Moreover, the contact angles of all Co40Fe40W20 thin films were all less than 90°, suggesting that Co40Fe40W20 thin films show changes in the direction of higher hydrophilicity. However, we found that their contact angles decreased as the grain size of CoFe increased. Finally, the Young equation was applied to calculate the surface energy of Co40Fe40W20 thin films. After post-annealing, the surface energy of Co40Fe40W20 thin films increased with the rising post-annealing temperature. This is the highest value of surface energy observed for 350 °C. In addition, the surface energy increased as the contact angle of Co40Fe40W20 thin films decreased. The high surface energy means stronger adhesion, allowing the formation of multilayer thin films with magnetic tunneling junctions (MTJs). The sheet resistance of the as-deposited and thinner CoFeW films is larger than annealed and thicker CoFeW films. When the thickness is from 10 nm to 50 nm, the hardness and Young’s modulus of the CoFeW film also show a saturation trend.

Effects of Annealing and Thickness of Co60Fe20Yb20 Nanofilms on Their Structure, Magnetic Properties, Electrical Efficiency, and Nanomechanical Characteristics

“…At an annealing temperature of 300 °C, as the thickness increases from 10 to 50 nm, hardness and Young’s modulus increase from 10.26 to 15.34 GPa and from 216.42 to 230.78 GPa, respectively. The experimental results demonstrate that although temperature does not significantly change the hardness and modulus, the hardness and Young’s modulus of Si(100) increase significantly as the film thickness increases, and the effect of thickness is significant [ 35 , 36 ].…”

“…However, when annealing at 200 °C, the behavior is different with respect to the other samples, as it is increasing. It can be reasonably assumed that the amount of oxides affects the surface energy [ 29 , 36 ]. According to the XRD results, the formation of more oxide layers on the thinner film surfaces results in increased contact angles and decreased surface energy [ 37 ].…”

Co40Fe40Y20 Nanofilms’ Structural, Magnetic, Electrical, and Nanomechanical Characteristics as a Function of Annealing Temperature and Thickness

“…Figure 8b depicts a graph of the Young's modulus of the CoFeY films, which exhibits an increasing trend with increasing thickness that progressively leveled out, with a maximum value of 235.9 GPa for the 50 nm thick as-deposited film. The experimental results revealed that the hardness and elastic modulus of the Si (100) substrate did not vary considerably with temperature; nevertheless, when the film thickness grew, the hardness and elastic modulus of the Si (100) substrate increased dramatically [35,36].…”