Kerr effect enhancement and corrosion resistance improvement by AlN and AlSiN films (abstract)

Abstract

RE-TM amorphous thin films with perpendicular magnetic anisotropy are promising for use in erasable optical recording media. In order to improve the drawback of easy oxidation and lower C/N of RE-TM films, some protective layers such as SiO, SiO2, ZnS, AlN, and Si3N4 films were studied.1,2 We have studied the Kerr effect enhancement and corrosion resistance improvement by AlN and AlSiN films. AlN and AlSiN films were prepared on glass, PC, and PMMA substrates by a rf magnetron sputtering system with three targets using low sputtering power. The films have a high refractive index (2–2.15), high optical transparency (over 90%), and high stability. The relation between optical properties and rf reactive sputtering conditions (Ar: N2 ratio, total pressure, sputtering power, sputtering time), composition, spectral transmittance, and uniformity of sputtering AlN and AlSiN films were studied. The Kerr rotation angle was up to 1.5° in AlN/TbFeCo/glass and AlSiN/TbFeCo/glass multilayer structures (laser is incident from air). We also studied AlN/TbFeCo/AlN/glass, AlN/TbFeCo/AlN/Al/glass, AlSiN/TbFeCo/AlSiN/glass and multilayer structure films. The results show that AlN and AlSiN films provide sufficient Kerr effect enhancement and superior corrosion resistance improvement to the RE-TM films. The microstructure of those films were also studied by JEM, XRD, and XPS.