Reactive sputtering of (Co,Fe) nitride thin films on TiN-bufferd Si

Epitaxial (Co,Fe) nitride films were prepared on TiN buffered Si(001) substrates by dual-target reactive co-sputtering method. With lower Co content, thin films mainly consist of (Cox Fe1-x)4N phase. With higher Co content, STEM EELS found no N signal in the thin film, and, combined with XRD results, shows that fcc Co is the main phase of the thin films instead of Co4N. The N2 atmosphere is helpful to induce the fcc Co phase formation during dual-target reactive co-sputtering deposition. For the films with less Co content, the RT magnetization measurements show similar magnetic properties as epitaxial Fe4N(001) films, while increasing the Co content, the resulting fcc Co thin films show biaxial anisotropy with the [110 ] in-plane easy axis. (orig.)