Electrodeposition of nanocrystalline CoFe soft magnetic thin films from citrate-stabilized baths

CoFe alloys have extensive applications in microelectronics and microelectromechanical systems because of their superior soft magnetic properties. With the advantages of simplicity, cost-effectiveness and controllable patterning, electroplating processes have been employed for CoFe film fabrication. In this study, stable baths with relatively high pH levels (natural pH) have been developed for CoFe alloy plating by introducing the complexing agent ammonium citrate as a bath stabilizer. The stability diagrams of CoFe plating baths were calculated using OLI Analyzer software. CoFe films with preferred composition, mixed fcc-bcc phases and 10-20 nm grain sizes, which have a saturation flux density Bs of around 2 T and coercivities of 8-17 Oe, have been electroplated from the citrate-added baths.