Characterisation of electroplated Ni 45 Fe 55 thin films on n-Si (111)
Résumé
Electrodeposition of NiFe films, on hydrogen-terminated n-Si (111)-H from acidic dilute sulphate solution, was studied by electrochemical measurements at room temperature in the presence and absence of saccharin. The electroplating process kinetics was investigated by voltammetric study and the effect of Fe2+ concentration on the deposit composition was studied as well with energy dispersive spectrometry analysis. The average composition of the Ni45Fe55 film was obtained for Fe2+ concentration in the range of [0.030–0.035] mol L−1 at a current density of −6 mA cm−2. Correlation between Fe2+ concentration in the NiFe deposit and electronic properties was examined by electrochemical impedance spectroscopy. Film roughness depends on Fe2+ concentration and a smoother deposit was obtained for the Ni45Fe55 film. Very low coercivity (less than 1.3 Oe) was measured in the Ni45Fe55 film with a nominal thickness of 640 nm. The very soft magnetic properties of the NiFe films provide information about the low level of inhomogeneities present in these films.