Determining Contact Angle and Surface Energy of Co60Fe20B20Thin Films by Magnetron Sputtering

This study examined the deposition of CoFeB thin films on a glass substrate at room temperature (RT), as well as the effects of conducting postannealing at heat annealing TA=150°C for 1 h. The thickness (tf) of the CoFeB thin films ranged from 100 Å to 500 Å. The microstructure, average contact angle, and surface energy properties were also investigated. X-ray diffraction (XRD) revealed that CoFeB films are nanocrystalline at RT and that post-annealing treatment increases in conjunction with the crystallinity. The surface energy of the CoFeB thin films is related to adhesive strength. The CoFeB films form a contact angle of larger than 90∘ with water as a test liquid. This finding demonstrates that the CoFeB film is hydrophobic. As tf increases from 100 Å to 500 Å, the surface energy at RT decreases from 40 mJ/mm2 to 32 mJ/mm2. During post-annealing treatment, the surface energy increases from 32 mJ/mm2 to 35 mJ/mm2, as tf increases from 100 Å to 300 Å; then it decreases to 31 mJ/mm2, as tf increases from 300 Å to 500 Å. The surface energy of the as-deposited CoFeB thin films exceeds that during post-annealing treatment at thicknesses of 100 Å and 200 Å, suggesting that as-deposited CoFeB thin film increases the adhesion