Combinatorial fabrication of magnetic multilayer films

Magnetic multilayer thin films are promising for applications in micro-sensor and high-frequency devices. To accelerate the materials development, nanoscale Fe50Co50/Co80B20 multilayers were fabricated in combinatorial deposition experiments: magnetron sputtering and photolithographic lift-off was used to generate discrete libraries of multilayers on 6 in. Si wafers such that the thickness of the constituent layers varied continuously across one direction of the wafer, remaining about constant in the perpendicular direction, i.e. wedge type films were fabricated. This was realized bymoving the substrate fromone side into and out of the sputtering plasma using a turntable and fixed shutters.Wedge type films composed of layers of one material were deposited to investigate their thickness distribution.Multilayers were fabricated by depositing thin wedge layers from two targets such that the increasing thickness of one material matched the decreasing thickness of the other. Film thickness, chemical composition, crystallinity, as well as static and dynamic magnetic properties weremeasured, partly automated. The multilayer properties across the wafer varied as intended, e.g. individual layer thickness from about 0.3–1.6 nm, saturation magnetization m0MS from 1 to 1.8 T, coercive field m0HC from0.024 to 0.25 mT, anisotropy field m0HK from 2 to 12 mT, and ferromagnetic resonance frequency fR from 2 to 4.7 GHz. Furthermore, non-linear dependencies of HC, HK and fR on the FeCo layer thickness were found. # 2003 Elsevier B.V. All rights reserved.