Iron–cobalt alloy thin films with high saturation magnetizations grown by conformal metalorganic CVD

Dense, smooth, and high-purity FexCo(1−x) thin films have been grown by chemical vapor deposition using a coflow of Fe(CO)5 and Co2(CO)8 precursors. High precursor fluxes and precise control over both the substrate temperature and relative precursor pressures are keys to reproducibly obtaining high quality films with the desired stoichiometry. Films with the composition Fe0.55Co0.45 show excellent soft magnetic properties: the saturation magnetization of 2.45 ± 0.05 T approaches the theoretical maximum, and the coercivity is less than 20 Oe. Conformal films have also been grown successfully in a trench structure with an aspect ratio of 4:1.