Preparation and characterization of electroless deposition of Co-Fe-B thin films produced by electroless deposition

The requirement for integration into silicon IC circuitry working at GHz frequencies drives the research into new development of both materials and processes. The formation of electroless Co\ue2\u20ac\u201cFe\ue2\u20ac\u201cB coatings was investigated on pure copper and 304 stainless steel substrates which were pretreated in a bath containing EDTA (20 g l-1), ethylene diamine (30 g l-1), PdCl2 (10 g l-1) and NaHPO2 (4 g l-1). Electroless deposition was performed at 348 K, for 2 h, in a bath that contained sodium tartrate (0.2 M) and sodium citrate (0.05 M) as complexing agents and the bath pH was adjusted between 6.5 and 9.5 using a concentrated solution of sodium hydroxide. The main components of the bath were a source of cobalt (II) ions, a source of iron (II) ions, DMAB as reducing agent and boron source, ammonium sulfate as buffering agent, phosphorous acid as a slow-rate reducing agent, a stabilizer, and an accelerator. Co\ue2\u20ac\u201cFe\ue2\u20ac\u201cB films having a variety of composition with respect to cobalt, iron, and boron contents were produced by varying the experimental parameters such as pH and the concentration of bath components. The coatings were characterized in terms of composition, structure and corrosion resistance by ICP and EDS, XRD and SEM, and by electrochemical instrumentation, respectively. The magnetic properties of the electroless Co\ue2\u20ac\u201cFe\ue2\u20ac\u201cB ternary alloy deposits were measured by a DC extraction method. The results indicate that tight control of process parameters enables the tailoring of coercivity and magnetic permeability of the films, and may lead to the microfabrication of innovative and efficient devices having nanofeatures such as nanowires.Peer reviewed: YesNRC publication: N